I “fixed” the VPN issue I was having. My built in VPN would also connect but not “ping” other servers within the domain. I manually added the search domains/servers to the VPN connection (Network->VPN Connection->Advanced->DNS tab. When that didn’t work, I also added them to my airport connection and voila, it worked… seems as if Apple is not forcing a routing through he VPN connection… my case I also tried the Cisco 2.4 osx client beta and the old client, neither worked for me despite uninstall/install.
Create two locations (Home/Office) so that you can keep the Airport settings intact for use at home. Also published this at the Apple Discussions board.
http://discussions.apple.com/thread.jspa?messageID=10355054
Hope this helps someone.

