After I read in the Event thread that people have issues with desert hill I guess that something might not be right with the installer.
After I've run the installer, Fall of Berlin was completely unplayable for me. I suffered from the same issues like recent crashes from the S&T pack.
Just to be sure I manually installed the 4GB Patch and the map has been completely fine.
Desert Hill is a pretty complicated map now with a huge amount of high quality textures from the newer vehicles. A test on this map didn't give me any issues after the 4GB patch.
The question for me is if the installer actually installed the fixed BF1942.exe. If certain conditions are matched the installer creates a backup file called BF1942.exe.bak before replacing the original exe. For a test could you please create a dummy BF1942.exe (for example renamed txt-file) and run the installer? Does it replace the file and create the backup?