game: GRAW1, fully patched (1.35)

when i try to log into a game it loads right up until you think it's gonna get into the server (right before the gear/team selection screen) and then it says "DISCONNECTED: UNKNOWN ERROR". i never had ths problem before (playing fine for 1+ years) and this started happening yesterday. sometimes, it lets me join a game, but then for the second map it says this error. could it be a corrupted map or something messing with graw? all i've done lately was install a few new map files (.bundle).
thanks for the help.

UPDATE:
1- I removed all maps and just left the single map that was on a server at the moment of testing and that solved nothing.. Doesn't seem to be map-related.
2- I re-installed the 1.35 patch just in case some file had become corrupted and that fixed nothing either.
3- Single player is working perfectly. Come to think of it, I hadn't played SP in a long time... Not sure if I played SP and then afterwards I started getting this problem connecting to MP servers... Can't recall, not sure if could be related.

Any help at all would be nice and a half. Thanks.

another update in my debugging quest:
i uninstalled and reinstalled my firewall. I was able to play for about 1 hr and about 10 map connections/map changes. i thought everything was fixed but now i can't join games again. could be firewall related but it's set on "allow all" and things aren't working. no further ideas.