We have recently upgraded from exchange 5.5 to Exchange 2003, and in switching our Unity(4.1) server to the new exchange server everything appeared to work but now we are unable to open the SA page. we receive the following error in IE with the heading "Login" I've made sure the unity user accounts exist in AD and have the proper rights assigned to them.

Unrecognized error

hr=0x80040154 (Class not registered )

From: global.asa -- Initialize()

Please see your system administrator for more details.

Any assistance would be greatly appreciated.