After installing SC2 and registering it on battle.net sometimes when starting the actual game this error appears: Association Required. This Battle.net account does not include an associated copy of StarCraft II. Please log into Battle.net account management and add the game to your account. No idea why this happens.
Funny thing is that this is the simplist thing to fix.
1. log into battle.net
2. goto Account >> Settings >> Communication Preferences
3. switch the language to match the play region
If the region and language already match up try changing your password a few times, sounds crazy but it seems to work.