Update: I just found the answer here: http://www.mail-archive.com/adwords-api@googlegroups.com/msg04562.html
This error occurs if you try to add a campaign to a MCC account. To fix just set the ClientEmail-Param in the auth.ini This works fine :-) -- You received this message because you are subscribed to the Google Groups "AdWords API Forum" group. To post to this group, send email to adwords-...@googlegroups.com. To unsubscribe from this group, send email to adwords-api+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/adwords-api?hl=en.
