Here's another tail from /var/log/syslog during the install.

Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/biosgrub
Jul 25 06:31:01 debconf: <-- 10 partman/progress/init/biosgrub does not exist
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS STEP 1
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/efi
Jul 25 06:31:01 debconf: <-- 10 partman/progress/init/efi does not exist
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS STEP 1
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/lvm
Jul 25 06:31:01 debconf: <-- 10 partman/progress/init/lvm does not exist
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> SUBST partman-lvm/text/in_use VG system
Jul 25 06:31:01 debconf: Adding [VG] -> [system]
Jul 25 06:31:01 debconf: <-- 0
Jul 25 06:31:01 debconf: --> METAGET partman-lvm/text/in_use description
Jul 25 06:31:01 debconf: <-- 0 In use by LVM volume group system
Jul 25 06:31:01 debconf: --> PROGRESS STEP 1
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/crypto
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> REGISTER partman-crypto/confirm partman-crypto/confirm_nooverwrite
Jul 25 06:31:01 debconf: <-- 0
Jul 25 06:31:01 debconf: --> PROGRESS STEP 1
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> PROGRESS INFO partman/progress/init/update_partitions
Jul 25 06:31:01 debconf: <-- 0 OK
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/linux-swap description
Jul 25 06:31:01 debconf: <-- 0 swap
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext4 description
Jul 25 06:31:01 debconf: <-- 0 ext4
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/text/primary description
Jul 25 06:31:01 debconf: <-- 0 primary
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/linux-swap description
Jul 25 06:31:01 debconf: <-- 0 swap
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/text/logical description
Jul 25 06:31:01 debconf: <-- 0 logical
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/filesystem_short/ext3 description
Jul 25 06:31:01 debconf: <-- 0 ext3
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/text/primary description
Jul 25 06:31:01 debconf: <-- 0 primary
Jul 25 06:31:01 debconf: --> METAGET partman/method_short/lvm description
Jul 25 06:31:01 debconf: <-- 0 lvm
Jul 25 06:31:01 debconf: --> METAGET partman/text/number description
Jul 25 06:31:01 debconf: <-- 0 #%s
Jul 25 06:31:01 debconf: --> METAGET partman/text/logical description
Jul 25 06:31:01 debconf: <-- 0 logical
Jul 25 06:31:02 debconf: --> PROGRESS STEP 1
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/filesystems_detected
Jul 25 06:31:02 debconf: <-- 10 partman/progress/init/filesystems_detected does not exist
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS STEP 1
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/auto_mountpoints
Jul 25 06:31:02 debconf: <-- 10 partman/progress/init/auto_mountpoints does not exist
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> GET partman/automount
Jul 25 06:31:02 debconf: <-- 0 false
Jul 25 06:31:02 debconf: --> PROGRESS STEP 1
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/autouse_swap
Jul 25 06:31:02 debconf: <-- 10 partman/progress/init/autouse_swap does not exist
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> METAGET partman/filesystem_short/linux-swap description
Jul 25 06:31:02 debconf: <-- 0 swap
Jul 25 06:31:02 debconf: --> METAGET partman/text/number description
Jul 25 06:31:02 debconf: <-- 0 #%s
Jul 25 06:31:02 debconf: --> METAGET partman/filesystem_short/linux-swap description
Jul 25 06:31:02 debconf: <-- 0 swap
Jul 25 06:31:02 debconf: --> METAGET partman/text/number description
Jul 25 06:31:02 debconf: <-- 0 #%s
Jul 25 06:31:02 debconf: --> METAGET partman/text/logical description
Jul 25 06:31:02 debconf: <-- 0 logical
Jul 25 06:31:02 debconf: --> PROGRESS STEP 1
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/backup
Jul 25 06:31:02 debconf: <-- 10 partman/progress/init/backup does not exist
Jul 25 06:31:02 debconf: --> PROGRESS INFO partman/progress/init/fallback
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS STEP 1
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> PROGRESS STOP
Jul 25 06:31:02 debconf: <-- 0 OK
Jul 25 06:31:02 debconf: --> RESET partman-target/arch_help/amd64/generic
Jul 25 06:31:02 debconf: <-- 10 partman-target/arch_help/amd64/generic doesn't exist
Jul 25 06:31:02 debconf: --> SUBST partman-target/arch_help/amd64/generic BOOTABLE B
Jul 25 06:31:02 debconf: <-- 10 partman-target/arch_help/amd64/generic doesn't exist
Jul 25 06:31:02 debconf: --> RESET partman-target/help
Jul 25 06:31:02 debconf: <-- 0
Jul 25 06:31:02 debconf: --> METAGET partman-target/arch_help/amd64/generic description
Jul 25 06:31:02 debconf: <-- 10 partman-target/arch_help/amd64/generic doesn't exist
Jul 25 06:31:02 debconf: --> SUBST partman-target/help ARCHITECTURE_HELP
Jul 25 06:31:02 debconf: Adding [ARCHITECTURE_HELP] -> []
Jul 25 06:31:02 debconf: <-- 0
Jul 25 06:31:02 debconf: --> SUBST partman-target/help KEEP K
Jul 25 06:31:02 debconf: Adding [KEEP] -> [K]
Jul 25 06:31:02 debconf: <-- 0
Jul 25 06:31:02 debconf: --> SUBST partman-target/help DESTROY F
Jul 25 06:31:02 debconf: Adding [DESTROY] -> [F]
Jul 25 06:31:02 debconf: <-- 0
Jul 25 06:31:02 debconf: --> SUBST partman-target/help FORMAT f
Jul 25 06:31:02 debconf: Adding [FORMAT] -> [f]
Jul 25 06:31:02 debconf: <-- 0
Jul 25 06:31:02 debconf: --> METAGET partman/text/scsi_disk description
Jul 25 06:31:02 debconf: <-- 0 SCSI%s (%s,%s,%s) (%s)
Jul 25 06:31:02 debconf: --> GET partman-auto/method
Jul 25 06:31:02 debconf: <-- 0 lvm
Jul 25 06:31:02 debconf: --> GET partman-auto/disk
Jul 25 06:31:02 debconf: <-- 0 /dev/sda
Jul 25 06:31:02 debconf: --> METAGET partman/text/scsi_disk description
Jul 25 06:31:02 debconf: <-- 0 SCSI%s (%s,%s,%s) (%s)
Jul 25 06:31:02 debconf: --> GET partman-auto/expert_recipe
Jul 25 06:31:02 debconf: <-- 0 
Jul 25 06:31:02 debconf: --> GET partman-auto/expert_recipe_file
Jul 25 06:31:02 debconf: <-- 0 /cdrom/preseed/lvm-map.recipe
Jul 25 06:31:02 debconf: --> FGET partman-lvm/device_remove_lvm seen
Jul 25 06:31:02 debconf: <-- 0 true
Jul 25 06:31:02 debconf: --> GET partman-lvm/device_remove_lvm
Jul 25 06:31:02 debconf: <-- 0 true
Jul 25 06:31:02 partman-lvm:   Logical volume "common" successfully removed
Jul 25 06:31:02 partman-lvm:   Logical volume "dom0-swap" successfully removed
Jul 25 06:31:03 partman-lvm:   Logical volume "dom0_0" successfully removed
Jul 25 06:31:03 partman-lvm:   Logical volume "dom0_1" successfully removed
Jul 25 06:31:03 partman-lvm:   Logical volume "dpm_0" successfully removed
Jul 25 06:31:03 partman-lvm:   Logical volume "dpm_1" successfully removed
Jul 25 06:31:03 partman-lvm:   Logical volume "svm_0" successfully removed
Jul 25 06:31:04 partman-lvm:   Logical volume "svm_1" successfully removed
Jul 25 06:31:04 partman-lvm:   0 logical volume(s) in volume group "system" now active
Jul 25 06:31:04 partman-lvm:   Volume group "system" successfully removed
Jul 25 06:31:04 partman-lvm:   Labels on physical volume "/dev/sda5" successfully wiped
Jul 25 06:31:04 kernel: [  186.509171] parted_server[12210]: segfault at b0 ip 00007ffa4a9cf8e4 sp 00007fffc9262f38 error 4 in libc-2.11.1.so[7ffa4a8a8000+178000]