Thank you for your reply. I should have mentioned that I have already updated yum after reading of a similar problem here on the forums. I am running yum-3.2.8-2.fc8, and the problem still persists.
I've added gnome-vfs2 to the exclude list in yum.conf as a temporary work-around. Now yum knocks me back with the error:
Finished Dependency Resolution
Error: Missing Dependency: samba-common = 3.0.26a-6.fc8 is needed by package samba-client
Error: Missing Dependency: rpm = 126.96.36.199-3.fc8 is needed by package rpm-python
Error: Missing Dependency: rpm = 188.8.131.52-3.fc8 is needed by package rpm-libs
Again, these packages exist on my system with the required version, according to "rpm -qa | grep samba-common" and "rpm -qa | grep rpm" respectively.
I'll continue to add these problem packages to the excludes line in yum.conf. Obviously it would be nice to get this working though!
Any more ideas?