Comment 1 for bug 95987

Similar experiences here. I had filled a pair of 320GB SATA drives with 5 RAID 1 partitions during an Ubuntu 6.10 install (ia32), then went to install 7.04 AMD64 Beta as an alternate boot option. When the partitioner loaded I selected manual partitioning.

At this point it would show only the physical RAID volumes, not the md* partitions. Selecting "Configure Software RAID" didn't seem to do anything interesting. Then selecting "Finish" produced "Could not stat device /dev/md/4 - No such file or directory.". That was with a plain text install, and as I recall it was the same if I chose an Expert install and loaded mdcfg, or if I tried to install the 32-bit beta.