did you do the following?
are you sure your not trying to join a old 5.1 server?
New to Nations At War thought you would give it a try.
Download the 5.2 Stand Alone exe...double click the .exe ...
the installation program will open and after a few "next"
clicks the program will find your BF2 mods folder and install the mod.
http://www.nawmod.com/downloads/NAW-MOD-5.2.exehttp://www.nawtek.com/downloads/NAW-MOD-5.2.exehttp://www.nawgame.com/downloads/NAW-MOD-5.2.exeAdditional Map Packs can be downloaded from the "Downloads" section.
these should be installed in order as they contain updates for prior released maps "sometimes".
http://www.nawtek.com/downloads/NAW-5.0-MAP-Pack-1.exehttp://www.nawtek.com/downloads/NAW-5.0-MAP-Pack-2.exehttp://www.nawtek.com/downloads/NAW-5.0-MAP-Pack-3.exehttp://www.nawtek.com/downloads/NAW-5.0-MAP-Pack-4.exeNAW MAP PACK 5 - Upgrades previous maps with map "id numbers,
loading map images as well as 3 fix's for
previously released maps and 7 new maps,
This should be installed last to update all previosly released maps.
http://www.nawmod.com/downloads/NAW-5.2-MAP-Pack-5.exehttp://www.nawtek.com/downloads/NAW-5.2-MAP-Pack-5.exehttp://www.nawgame.com/downloads/NAW-5.2-MAP-Pack-5.exe