=== modified file 'casper/scripts/casper-premount/20iso_scan'
--- casper/scripts/casper-premount/20iso_scan	2008-03-06 08:36:38 +0000
+++ casper/scripts/casper-premount/20iso_scan	2008-05-06 23:22:42 +0000
@@ -29,5 +29,15 @@
     if find_path "${iso_path}" /isodevice rw; then
         echo "LIVEMEDIA=${FOUNDPATH}" >> /conf/param.conf
         echo "LIVEMEDIA_OFFSET=0" >> /conf/param.conf
+    else
+        panic "
+Could not find the ISO $iso_path
+This could also happen if the file-system is not clean because of an operating
+system crash, or an interrupted boot process, or beacause of an inproper 
+shutdown, or if a removable device was unplugged without unmounting/ejecting 
+it first. To fix this, simply reboot into Windows, let it fully start, log in,
+ideally run a chkdsk /r, then gracefully shut down. Once you restart, 
+you should be able to resume the installation.
+"
     fi
 fi

=== modified file 'casper/scripts/casper-premount/30custom_installation'
--- casper/scripts/casper-premount/30custom_installation	2008-03-06 08:36:38 +0000
+++ casper/scripts/casper-premount/30custom_installation	2008-05-06 23:22:42 +0000
@@ -84,8 +84,18 @@
         if [ -e /custom-installation/preseed.cfg ]; then
             cp /custom-installation/preseed.cfg /
             #fix parameters that cannot be set from a non-linux OS
-            fix_preseed /preseed.cfg "$custom_installation_dev"    
+            fix_preseed /preseed.cfg "$custom_installation_dev"
         fi
+    else
+        panic "
+Could not find the installation files $custom_installation_path
+This could also happen if the file-system is not clean because of an operating
+system crash, or an interrupted boot process, or beacause of an inproper 
+shutdown, or if a removable device was unplugged without unmounting/ejecting 
+it first. To fix this, simply reboot into Windows, let it fully start, log in,
+ideally run a chkdsk /r, then gracefully shut down. Once you restart, 
+you should be able to resume the installation.
+"
     fi
     find_path_cleanup
 fi

=== modified file 'debian/changelog'
--- debian/changelog	2008-04-22 14:57:59 +0000
+++ debian/changelog	2008-05-09 16:07:42 +0000
@@ -1,3 +1,10 @@
+lupin (0.17) UNRELEASED; urgency=low
+
+  * Provide a clearer error when required installation files cannot be
+    found (LP: #226622)
+
+ -- Agostino Russo <agostino.russo@gmail.com>  Wed, 07 May 2008 00:22:00 +0100
+
 lupin (0.16) hardy; urgency=low
 
   * Tighten /proc/mounts test to avoid e.g. /dev/sda10 matching a search for