"File sum/name mismatch"

[Pedsdude]

This error is almost always because you have too many .iwd files in your mod folder, and/or you have too many maps in the usermaps folder.

Put the map.IWD in it

You only need to do this if you're hosting a server to fix the download loop bug - for local play, it's not necessary.

[Pedsdude]

I've never taken the time to check which one it actually is... whenever I get the error I just do both!

- Go to CoD4\mods\codjumperv3_1 (or whatever mod version you're using)
- Remove (just move out, don't delete) all .iwd files other than the z_cod4jumper.iwd file (i.e. all the jump map iwds)
- Try and play the map
- If it still gives the error, go to CoD4\usermaps and move out all map folders apart from the one you want to play