Ok...since 1.4 is out...TOO MANY dude post about how they have problem with patching.
I see too many ( you have to re-install from scratch...)

THIS IS THE BEST WAY TO PATCH WITHOUT PROBLEMS.

(If you have enough Hard Disk space) Create a Copy of BattleField 2 Folder located in :

C:\Program Files\EA GAMES...

This will give you a second folder named "Copy of BattleField 2"...

Patch the game....if any problem occur, delete BF2 folder, rename The 2nd folder back to it's original name. and repeat the process...

Once your satisfied about how the game plays...delete the backup folder or Burn it to a CD/DVD just in case.