Verizon Wireless + VPN

Hey folks,

I am having a VPN issue at work. Standard disclaimer applies in that I’m by no means a reliable source of network information, though I get by. At our office we are able to VPN in using Microsoft VPN/PPTP/whatever. As far as I can tell, I can VPN in from any machine at any time. However, if anyone here uses a Verizon Wireless USB card, it is hit or miss whether or not they’ll be able to connect. If it fails, it fails with error 678. So, as far as I can see, our VPN setup is fine. Has anyone run into a similar issue? I’ve tried VPNing in from several machines, and setting up Verizon Wireless access manager on those machines. Same problem.