Comment 22 for bug 571999

Some testing confirms how to reproduce this bug, and that it's actually an issue with apt:

On 9.10:

Install wine1.2 package. Then Install wine package. Apt will remove Wine1.2 (since they conflict) but leave the wine1.2 deb in the cache.

Upgrade to 10.04. This upgrades wine to the dummy package, which depends on wine1.2. Apt then tries to install the Karmic wine1.2 from the cache, which still conflicts with wine, and it then panics and gives up. Apt should instead first try to upgrade wine1.2 to the lucid wine1.2, which doesn't conflict with the new wine.

We can probably work around this by releasing an SRU for Lucid wine1.2 that has the wine dummy package depend on a wine1.2 newer than the one in Karmic.