OS: Windows 7 64bit Home Premium
VPN Client: Shrew Soft

Updates installed:
Definition Update for Windows Defender - KB915597 (Definition 1.75.1050.0)
Security Update for Windows 7 for x64-based Systems (KB971468)
Cumulative Security Update for ActiveX Killbits for Windows 7 for x64-based Systems (KB978262)
Security Update for Windows 7 for x64-based Systems (KB975560)
Windows Malicious Software Removal Tool x64 - February 2010 (KB890830)
Update for Rights Management Services Client for Windows 7 for x64-based Systems (KB979099)
Security Update for Windows 7 for x64-based Systems (KB978251)

Solution:
Turned off firewall for internal / private networks