SecureClient for OS-X and parallels NAT

HI,

I'm using a MacBook Pro, with Parallels running Windows XP (it's a VM
that allows running XP as an application in OS-X).

Parallels supplies networking to the XP on the VM via a NAT service in
OS-X. The VM connects to the NAT service gateway, and the NAT uses the
Mac's internet connection.
Usually this all works fine.

Now, I also need to connect to my office network using a CheckPoint
SecureClient VPN-1 for OS-X. So I installed SecureClient, and since
then the VM is having network problems. I can get DNS services and
ping from XP, but nothing else works. From OS-X I have no trouble with
connecting, and everything works fine.
I'll note that just installing SecureClient creates the problem, even
when I'm not connected with it to the office.
Uninstalling it solves the problem.

I'm not sure, but I'm guessing SecureClient's firewall somehow blocks
trafic coming from the NAT network interface for some reason.

I'm connected to the internet via a cable modem and then a PPTP VPN to
my ISP.

Is there any way to configure SecureClient to solve this?

Any help would be appreciated.
Yaron Tadmor