Salute!
I have mekmatch working but since my original MW4 is not up to date and although I have the updates DL'ed I have yet to install them. I haven't done so because....well....I must admit I still have problems unzipping files without really good instructions included. Right now the pr3 and updated Maps are sitting on my Desktop in a Temp Folder. Ahem.... yes, thats right, I've learned a lot over the years but I'm still in the dark on some issues. Just Me bein Me. That's as good as it gets. And as I age further I shudder to think about what's comin. 
Ok enough ramblin. I believe that IF I can get those Maps installed correctly I will have more Join Options available. I have tried several times trying to join the Salvage Server but I get that "you don't have the correct map message". Many of those maps are either updated MW4's or some custom job. I click on yes to go to the DL location to get the map and of course the page no longer exists. 
I have even posted my troubles on Mektek and low and behold I'm sent to non existant pages as well. In final desperation I put my MW4 disc in and PoP! up comes the MS MW4 Site with the pr3 and Map Updates (at least I think they're the latest) and DL'ed them. This long winded story brings me back to the final issue of unzipping them and placing them in the correct files, then copying and pasting them into the correct Mercs Folder. I understand all the rest It's the fact that Unzipping is sketchy and I won't even try it unless I'm sure of what I'm doing???
A very frustrated Warrior indeed.
Regards to all!
DSA WarHorse....Out.