The email address validation (the preg_match()) does not work with the email address that is inserted into the email field by the facebook connect module.
Here is an example email address for a facebook connect user:
apps+120942577124.1269123383.b5455a061de7e4a65d60674fc8530fa5@proxymail.facebook.com
Because the validation rule won't accomodate this address the user is unable to add/change any of his profile settings INCLUDING his membership type.
You can duplicate this error by creating a facebook connect account and then trying to edit the profile. You will be unable to save changes due to the validation failure.
