BF2S Forums O.K Can someone please help me out.

I got BF2:SP today. I got home and put the first disk in to download it. then it ask me to put disk 2 in, so i did. Then when it was finished it asked if i wanted to download gamespy arcade( i was wondering if i had to ar not because i already had if for original BF2) so i downloaded it just to be safe. then i went to play the game it loaded up right and everything.  i chose a server to play in. as soon as it finished loading up i clicked on join game.then it took me back to the screen where you choose a server to play in and said "This server only allows players with unmodified content to join. Revert back to your version of BF2 to the current official version to join" those were the exact words it said. i dont have modified content or anything like that i just downloaded the game and started it up. So could someone please tell what i could try or even tell me the problem.