Can`t join any game

If i want to join a EF game it always says: "The host uses a different mod" my friend can join everyone...we got exactly the same versions ef: 1.3 and COH: 2.601.0 why i cant join EF games?

I'm not sure, but I guess there was small update after 1.3... like 1.301 or something like this.
did you or your friend modified EF files in any way? This can cause some problems...

There're a couple of updates(1.301 && 1.302) that you need to download/install after 1.30 is installed.

Also, make sure you aren't using skin mods.

well i just downloaded and installed EF and my friend to its the only mod we installed we patched(missing datas and maps) but still cant play

Well, this is the reason of the error you are facing:

http://easternfront.org/forums/index.php?topic=1677.msg56633#msg56633