Google Apps transitioned accounts can be a little tricky.  If you have a Google Account with your personal domain (@domain.com instead of @gmail.com) the simplest way to remedy is to remove your @domain.com from the Google Account.  You can then transition the account to a stand-alone @gmail.com account.

Once your @domain.com is removed from the @gmail.com account, you should then be able to transition your Google Apps account fully to the Google Accounts/Services.

If you get stuck on this phase, please contact us here by opening a new ticket.