Is the problen system-wide?
Can you search the users using the Global Directory? If no, can you login to DC Directory Administrator and see the users there? If you cannot login to DCD Admin or donot see any users there, try fixing DC Directory.
If you can see the users in Global Directory, try this:
Stop IIS Admin Service, then run the following script: c:\ProgramFiles\cisco\bin\xmltemp\installxml.vbs Then start IIS Admin Service and test the corporate directory again.
Thanks,
Partha