1. Update Modern Warfare 2 by executing "iw4mp.exe"
2. Rename "iw4mp.dat" into "iw4mp.dat.exe"
3. Download and Copy&Replace over the original file located in your Modern Warfare 2 Folder.
4. Run "iw4mp.dat.exe" and Run ModLoader. (DONT run "iw4mp.exe" ever again, ONLY run "iw4mp.dat.exe")
5. ModLoader should now work.
This will likely not even work on the official aIW server. Older versions of steam_api.dll are not allowed to connect to the official server anymore, and renaming iw4mp.dat is not necessary to do on a personal aIW server.