If you installed Fedora 7 using the 6.93 Development Live Image then it probably configured yum to use the development repositories. I have had problems with XFCE4 specifically the terminal application exiting when I click the `Terminal' menu option.

Because 6.93 wasn't the main `7' release it enabled the development repository so I never got stable packages.

The Answer:

Install 6.93 off the LIVE CD
Immediately download and install the Fedora 7 Release RPM (fedora-release-7-3 & fedora-release-notes-7.0.0-1) from the `7' yum repository and not the development branch
Run yum update using the stable 7 series rpms

Problem solved