Based on past cases there could be a few things causing this.
The first thing to do is deploy sqlserver 5.10 and retest all the failing profiles.
There are cases where it was a failure at the OS level and resolved via installing the OS service pack for Windows 2008 R2.
The other thing known to cause the problem is a basic communication problem.
telnet can be used to test connectivity, and Wireshark is the tool for capturing network traffic.