so i download this map file... but what i get is afile with a .pmp extension and in the maps folder in soldat all the maps are .pmp .
so... is there somthing i can do about it to play the map or is the file just bad?

I think you mixed something up ;)
PMP is the old map file format and PMS is used by the new map maker.
You can use the official map maker to open an old .PMP file and save it as the new .PMS, but sometimes things get lost while opening the .PMP
Maybe you'll have to place spawn points or something like that.
If you have problems doing that, post the link to the .PMP here and someone will take care of it.