Having problems installing ExpressViewer on WinXP

I'm having problems installing Autodesk's EpressViewer on my WinXP stations.
I'm getting the message:
0001\F7\AdPageView.dll
There was a problem registering this file
The installation will be cancelled
But the Installation does continue after I click OK on the error message
(above)
Then then I go to open ExpressViewer I get the messages:
Invalid Class String
Can any help with this problem?