Oi,
Step 1
You need to decompile the mod.ff with an extractor. (FastFile Exporter – Tom Crowley)
Step 2
Put all these files you see in your mod path, should look like this:
Step 3
Go to Call of Duty 4 - Modern Warfare\Mods\3xp_movie\maps\mp\gametypes
and open dm.gsc and cj.gsc and look for "mp_dm_spawn" and replace it with "mp_jumper_spawn"
That's it, have fun recording.