buddy, check the TCP Flow Control Channel, i am sure you have two of
them... one outside the VPN and 1 inside the VPN... this add too much
weight to packets try to create a TCP/IP vpn over UDP over IP (sound
wierd)

if not, check you ipsec configuration, IPSec is really tricky, if you
can switch to SSL it is easier and faster... and i think is safer than
IPSec