I'm back,
After some thoughts, the problem seems to be an uppercase or lowercase ... Did you typed it correctly ?
Now, about to insert a new user, you can do it by Inserting a line into the " user " table via the upper menu on MySql
You must take care to use a new "user_id" and set the "status" field to 1 and the "creator_id" field to 1
But your problem seems to be very strange... Are you sure to have enough space on your disk server ?
Alain
