VPN disconnects after 2 minutes 1 second

I'm trying to VPN into my companies network but when I do
I always get disconnected after two minutes and 1 second.
I've contacted the IT department and their logs show that
the disconnect was requested by the user (me) but I'm not
forcing a disconnect!

I've checked the settings for the VPN and it's settings
are set so that it never disconnects regardless of idle
time.

Has anyone else had this problem? And if so, how did you
correct it.

My system has WinXP SP2 installed on it.

Thanks!