Description of problem:
I tried to upgrade an F14 machine using the F15 Alpha RC 1 DVD and it failed.  Anaconda reported a dependency error but when I clicked on it for details, the dialogue box was blank.  

Version-Release number of selected component (if applicable):
Alpha RC1 DVD from:

http://alt.fedoraproject.org/pub/alt/stage/15-Alpha.RC1/Fedora/x86_64/iso/Fedora-15-Alpha-x86_64-DVD.iso

How reproducible:
Every time.

Steps to Reproduce:
1. Insert installation DVD.
2. Reboot F14 machine.
3. Choose to upgrade (had internet connection.)
  
Actual results:
After upgrade initialises, a dependency error is reported.  Clicking on the error for details of the mismatched files brings up a blank dialogue box.

Expected results:
Upgrade should proceed without problems.

Additional info:
The machine in question had a fairly standard F14 installation.  Every package had been installed from the yum stable repo apart from Firefox 4 nightly and LibreOffice.  Since the dialogue box did not display any details, I am not sure what dependency broke the upgrade.