Cfant it sounds to me like you need to patch the game, though if you patch to the very latest version number the game will probably look extremely alien to you as Crusader Kings II has evolved a lot since you last updated it :happy:
Since you seem to be a bit out of the loop I just thought I should mention we have discontinued supporting GamersGate(Of course you are still free to use it) so we gave everyone free Steam Keys who had bought the game on GamersGate, it should be in your library on GG if you decide you want to switch.
To solve your problem with the Legacy of Rome DLC you will have to download a patch from GamersGate or else the game won't get the new mechanics from the DLC.
The Patch for Legacy of Rome was v1.07
http://www.ckiiwiki.com/Patch_1.07
Since you seem to be a bit out of the loop I just thought I should mention we have discontinued supporting GamersGate(Of course you are still free to use it) so we gave everyone free Steam Keys who had bought the game on GamersGate, it should be in your library on GG if you decide you want to switch.
To solve your problem with the Legacy of Rome DLC you will have to download a patch from GamersGate or else the game won't get the new mechanics from the DLC.
The Patch for Legacy of Rome was v1.07
http://www.ckiiwiki.com/Patch_1.07