Web Access Revcovery!

Hi There

We are running IIS and Exchange Server Web access on the same system. Due to couple of reasons we reinstalled IIS. After reinstalling the IIS, we added Virtual director for Exchange Web Access. After adding this we are not able access the mail box by using the Web Access. We are getting the following error message:

You might not have permission to view this directory or page using the credentials you supplied.

Is there any way to recover the system with out re installing theWeb Access. Any help is appreciated.

Thanks,
Raju