Problems with Installing codjumpper mod in cod4!

[deluxe94]

Hey community,

I wanted to play the codjumper mod AND the custom maps for it on an own LAN-Server. But i have the following problem:

I downloaded the maps from this site and put the files in the Call of Duty 4\usermaps\mp_codjumper_training (just as example) folder.
Then i run the iwmp3.exe and opened an own lan-server. (Free 4 All, any map)
Then i wanted to load a custom map so i typed this in console: /map mp_codjumper_training (just as example)
But the game didnt made what i expected. It loads a quarter of the map and suddenly an error message appears and the game closes. Error Message:

"Impure Client detected. Invalid .IWD file referenced! .usermaps\mapname\.iwd file"

I really dont know what to do cause i tried almost every custom map i found here on this site for cod4.
But theres something else i dont understand.
mp_peds_propal works! But i guess its because this is the only custom map that i already played on public (Codjumper Server #3)
Please Help me!
Thanks in Advance
Dignity

[Drofder2004]

Are you loading the codjumper mod?

When you open the iw4mp.exe file, click "mods" then double click "codjumper".

[BlueDamselfly]

Put your maps files in your mods/codjumper folder and in your usermap/X folders.

Should work then, and as drodfer said, obviously don't forget to start up the mod