Each time i try to register as a new user in my site with this name: Morribirecords .. after registering.. when i edit the profile.. logout and try to login again the browser will bring ...Error 500 Internal Server Error. 

I have to delete the account, clear my browser cache  before the entire site works  again.... what is wrong with the name or is it having any clash inside the server.. 

 I ran debug and got the following message.. check screen shot.