Cannot negotiate authentication mechanism
You are using client does not support SASL authentication. You must have a client that uses Subversion version 1.6 and higher and on Linux must be installed package cyrus-sasl-md5. If you compile Subversion on Linux by yourself, you must use option –with-sasl.
Revprop change blocked by pre-revprop-change hook
You are trying to make additional changes of the properties but it is forbidden for this repository. This feature must be enabled in the Customer Center in repository detail, by the choice allow additional changes to revision properties (pre-revprop-change hook).