Shedds,
Got from one of the fellow Forum Customers.. think this might be it, we are working on getting this into the release-notes..
"Versions 3.1 and 3.1.1 vpn client would connect, but would not transfer any data. Disconnects would occur immediately or within 30 seconds. No errors in client log or concentrator log. MTU was adjusted, IPSEC thru NAT was tried, etc... Upgraded AT&T Worldnet dialer v3.2.1 to v3.2.2 and that resolved the problem."
Hope this helps,
Aamir