ATT GSM Wireless-to-Cisco 515E Remote vpn

I am trying to establish a Remonte-vpn tunnel to my main site which is behind a cisco pix 515E.
Remote is a Laptop connected to ATT blackbery 8310 (Wireless network is ATT GSM)
The GSM network is fine —- takes me to internet and I can browse
I am using a Cisco VPN CLINET to establish the connection

Tunnel cannot be established

Does anyone know if this can be done?

Thanks