Disable Open File - Security Warning when running .exe WinXP SP2

Hi,

I am trying to deploy an application remotely in my Windows 2003/XP SP2
network. It is from a third party with 3rd party remote deployment software.
It worked fine until MS introduced all the "extra" security features with
Windows XP SP2.

Now it won't deploy automatically because of that really annoying Open File
- Security Warning. For some reason because it is running off my internal
network, it thinks it is from the "internet".

Is there a Group Policy where I can disable this Dialogue box from opening?
There is the "untick" option, but I have 300 machines I am trying to deploy
this to and I don't want to logon to each individual machine.

If not a Group Policy than a reg key hack?

I appreciate MS adding security but in my internal network it is far more of
a hindrance than a help.

Cheers,

Lara