Pantech UML290, 2107 error code on Windows XP

I have a Pantech UML290 modem and I cannot connect to the Internet. Every time I try to connect I get an error popup indicating that there was an error connecting (error code 2107). I've uninstalled and reinstalled the VZAccess software several times with no luck. Just today I installed the same software on a different laptop sitting right next to the one I'm having the problem on and I had no problem establishing a connection and maintaining it for more than an hour. So it's not a UML290 modem or wireless network issue.

I actually originally had it working but the connection would drop every 3-5 minutes. I got frustrated and upgraded the firmware on the UML290 about a month ago. Ever since the firmware upgrade I can't even connect any more on this laptop.

Doing a Google search I've occasionally seen some possible conflicts between the VZAccess and Cisco VPN client software. I have several different Cisco VPN client applications installed but I need to leave them installed for work purposes. I also tried to put the VZAccess/modem into LAN mode using a separate utility but that didn't help.

I'm running Windows XP SP3, VZAccess Manager version (2703h), Pantech UML290, firmware L0290VWBB12F.248, hardware version REV_03.

Any suggestions? Any way that I can roll back the firmware upgrade on the modem?