Looks like I have exactly the same problem. Gold edition crashes with 'Operationflashpoint has caused as error in ~DF394B.TMP.' error message.
Gold Upgrade installs but when I try to run it, same story. Patch 1.46 crashes during installation with the same error.
I have run the CHECKOFP tool, it says everything's perfect.
I have WinMe, Athlon 1.1 GHz, GeForce 3, 256 MB RAM.
Any ideas?