Does Shareport work with VPN?  I haven't seen VPN specifically mentioned with respect to Shareport.  
I can get Shareport working on my Dell that does NOT run VPN.  However...
I can only get Shareport working on my company laptop IF I don't start VPN.  If I start VPN, the printer no longer shows up in the Shareport Utility.  Further, I need to turn off Cisco Security Agent so it can print.  Turning off Cisco Security Agent isn't a deal-breaker, but not being able to print while running VPN is a deal-breaker.  My VPN is Nortel Contivity V04_86.102 running on Windows XP.  
Below are the router, firmware, and sharepoint versions:
Router DIR-628 hw ver A2, Firmware version 1.20NA,  2009/04/24
Shareport version 1.1.0 R1
Thanks!