Here is what you need to do to be able to play in PB enabled servers. First download pbsetup. Those of you who played CoD4 will be familiar with it.
http://www.evenbalance.com/index.php?page=pbsetup.phpRun it and add America's Army Version 3. Direct it to the appropriate folder.
Deploy Clientx86 (32bit) Windows
C:\Program Files\USArmy\America's Army 3\Binaries
64bit Windows
C:\Program Files (x86)\USArmy\America's Army 3\Binaries
Steam Downloadx86 (32bit) Windows
C:\Program Files\Steam\steamapps\common\america's army 3\Binaries
64bit Windows
C:\Program Files (x86)\Steam\steamapps\common\america's army 3\Binaries
Last, click Check for Updates.