Another Clue
Whatever this problem is, it also affects uploading files in the DNN File Manager.
Working directly on the Console of the Server and logged in with the default Host account, here are the steps to I follow to reproduce the problem.
1. Upload a small (50k) zip file to a folder
2. Delete the file
3. Upload it again.
4. Browser stalls after a minute
If the file is larger, say 130k, it will not upload at all.
The end result is the error reported in the first post of this thread and IIS will not restart. A server reboot is required to fully clear the problem.
I know this could possibly be a Server/IIS/SQL configuration problem since there is no error in the DNN Event Viewer. The only error I get is the one from my first post in this thread.
I have installed DNN dozens of times through the ealiest versions of 4.x through 5.2.2. and have never seen a problem like this This is my first attempt at a clean install with 5.3.1 on a new server so It's hard to tell if it's DNN or the Server
Any help, guidance, or conjecture would be appreciated.