I am having the same issue where i cannot edit the content on the portal:
http://social.microsoft.com/Forums/en-US/c55ee4e4-1554-4489-b0ee-a5370c53cf6e/crm-2011customer-portal-unable-to-edit-content?forum=crmlabs
I followed this forum post and multiple others and still cannot get it to work. We are using Windows Server 2012 R2 with forms based authentication. Is there something different that has to be done for that set up?
These errors appear to be generated when the site tried to access “/Services/cms.svc”.