To claim a plot you press right mouse button and to unclaim you press left.
In order to claim he needs a deed paper and a claim stick.
Sounds like he is pressing the left. ;)
Been playing for around 3 days on a server i host and yesterday it went down due to a stackoverflow but I could restart the server with no issue. Last night it went down with the same reason again and now I'm unable to start it.
It goes thru the entire process but after finishing the Server initialization it ends with a stackoverflow.
EDIT: After a lot of fiddeling around I uninstalled the server program and deleted all folders to it and then reinstalled and added the latest back up which seems to have fixed the issue.