When attempting to access a WVC210 camera using IE9, I get a "File Not Found" error. I've updated the firmware on the camera to V188.8.131.52, and have reset the camera to factory defaults. Under "Downloaded controls" in IE, it indicates that the Linksys210Viewer Control is enabled. I can assess the camera just fine using Firefox, but not with IE9.
I have had this exact same error on two different cameras. I installed the upgrade from a Windows 7 machinge on camera A. I can access the camera A from Windows 8 (with full functionality), mac and iPhone. But not Windows 7 (IE9). For camera B, I installed the upgrade using my Windows 8 machine. I can access the web interface for camera B from Windows 7, mac and iPhone, but NOT from the machine I installed from.
I believe this is a browser issue, and have not completed the troubleshooting. BUT, this should give you enough information to go into your IE9 and determine what may have changed. If you resolve before me, please post.