I recently configured my SharePoint environment for smart card
authentication (CAC) and since I have done that I am now having a
number of issues. The most problematic of which is that now random
Office documents (Word, Excel, and Powerpoint) cannot be saved after
editing. The user clicks the diskette icon of goes to File > Save As
or Save and gets an error message;

The web server has a problem. Please try again later or contact your
system administrator.

Nothing in the SharePoint logs about what is causing this and nothing
in the Event Viewer.

This is just one of several issues I am having. I know it is directly
related to the smart card authentication, if I go in and reconfigure
my user account so that I can use a username and password and not a
certificate and PIN everything works fine.

Possibly something between Office 2003 and certificate based
authentication? Any thoughts and ideas are much appreciated!!!!!