Ampache's XML errors are loosely based around the HTTP status codes. All errors are returned in the form of an XML Document however the string error message provided is translated into the language of the Ampache server in question. All services should only use the code value.
<root> <error code="501">Access Control Not Enabled</error> </root>
All error codes are accompanied by a string value for the error and derived from the HTTP/1.1 Status Codes