We have experienced problems with TechDoc and SharePoint sometimes hanging when using AVG Anti-Virus Business Edition 2011.
The problem is caused by the personal email scanner. It aggressively grabs many ports on the installed system when configured to scan incoming email. The current solution is to not install the personal email scanner or to disable scanning of incoming email in the advanced settings.
We typically use Outlook to read mail so we only install the Outlook email scanner, which does not exhibit the problem.
The problem has been verified to exist in all versions of AVG 2011 up to and including 10.0.1204. The problem has been reported to AVG Customer Support.