I can't tell you how it happens, but I can tell you that if you reinstall Windows Server 2003 service pack 1, it fixes the problem. Apparently, there are a couple of corrupted files in the System32 folder, one of which is plugin.ocx which cause the problem. Running SFC did not fix it, it said it couldn't overwrite the files in question. I worked with a Symantec Advanced Support Rep, and he says he's seen dozens of them, and the only thing in common was the original install was done from an Nlite CD. That's why I'm here, trying to find a solution.