I downloaded all the v2 MIBs from http://tools.cisco.com/ITDIT/MIBS/MainServlet?ReleaseSel=3775&PlatformSel=85&fsSel=33.

When I go to MIB Repository and try "Add the MIB Folder Path", it tells me "Added 0 file(s) in MIB Repository successfully."  If I try to randomly import one of the MIBs, it will often tell me that some other MIB needs to be imported first. 

It's been a frustrating experience.  With a different application we have, I gave it the folder and it quickly imported all the MIBs.