Locked me and all users out

Spent a day and a half locked out, (and all members of the site also out) no idea why, edited db to change admin pw etc, then archived this Custom Url plugin by ftp (ie, put an x in front of the name) and hey presto, all back to normal (without the changed login url obviously).

So have to give this a one star as I just lost a load of time back and forth with host etc, and was just a malfunctioning plugin.