HSDPA

I am connecting to the internet using HSDPA. I also have to run Nortel’s Contivity VPN Client. However when I try to log onto the VPN client it logs me out he moment I am connected, stating that the connection has been lost and I should re-connect, whereupon the same happens again. The client I am using is V04_15.06 and I am using a HUAWEI HSDPA USB MODEM to connect to the internet. Any ideas on this would be appreciated.