A patched version of the QubeGUI has been uploaded to the ftp site, available at:
/pub/qubegui/current/qubegui-6.4.0-a.x86_64-FEDORA-14-x86_64.rpm
The issue was related to the presence of jobs in the 'dying' state in the job list, a typical error included the error message:
KeyError: 261L
The patched version will show "6.4.0.a" as the version string in the window title bar.