There have been a handful of early adopters of the Verizon Wireless V640 (Novatel V640), that have discovered their MacBook Pro and V640 card do not work with Cisco VPN. This VPN Issue is not present if you boot your MacBook Pro under BootCamp/Windows XP.
According to sources at Cisco, they are currently testing a fix and it should be released to the general public in the next few weeks.
For the latest news on this topic, see the following thread on EVDOforums.com:
EVDO with VPN with MBP with 640 card - ISSUE