Yes, you need some patches: go to the developer's download site,
http://www.papy.com/framesets/downframe.htm and download and install the
following patches (I don't think order matters but this is the order I
installed them in):
1.2 patch (must be done first!)
disconnect fix
Direct3D patch
Be sure to read the "readme" files for each patch carefully.
All that being said, though, GPL is going to run quite poorly on your PC.
Your graphics card and RAM are fine but your CPU is barely strong enough to
run it. Sure you meet the minimum requirements on the box, but they were
optimistic to say the least.