First, I have no Latin training and only limited Polish, but with a few useful tools, I can stumble my way along.
I believe the previous interpretation of advocatus pagi may be correct. It seems to translate as a legal assistant or advocate for a local area such as a village. This seems to be a useful translation tool: http://archives.nd.edu/latgramm.htmhttp://archives.nd.edu/latgramm.htm
As to the other term,"szuberberk," I wonder if your transcription has the word spelled correctly?