+1  A: 

It is not actually a COM error, it is a Windows error, wrapped in a COM error code. It is a very low-level error, little can be distilled from the error code or the stack trace. There are plenty of hits when you Google the message, here's one that looks good. Be sure to find more yourself if that's not a good match.

Hans Passant
Thanks!! Impersonation was enabled on the Web Site in global configuration for ASP.NET, and disabling it fixed my problem. Not sure how it got enabled in the first place.
Josh Stodola