At this point the install will let me retry forever, but not skip the package and continue on. Is there any way to work around this? The md5sums of the .iso files are correct, so I don't think I've had a download problem.
I happen to be installing the software under VMWare (version 3.0, running on a Windows XP host). I've swapped the .iso files by suspending the virtual machine and "swapping cdroms" by renaming the .iso files on my hard drive. I've used this technique many times, and it worked for 20 minutes following the switch, so I don't think this is likely to be the problem.