We've been having the same issues with WeBWork2.8/ubuntu12.04 that you mention:
1)cannot browse the OPL by category
2)cannot use the "add" to target set button
3)using the rerandomize icon causes errors
(but email functions)
I noticed the summary from your IT support. May I ask exactly what was done to solve the problem? My IT person would be interested.
Any details would be appreciated.