I would delete everything via FTP (actually if you have cpanel, the file manager will be quicker) and then go into phpmyadmin and delete the database. You could alternatively just install it on a new database as well if your not comfortable with deleting the old one. I would shy away from trying to use the current database without dumping it first as an entry in that database is probably causing this is.
Another small possibility is that maybe somebody around here can confirm that this setting is in your database and tell you how and where to delete or alter the mysql entry, possibly bringing your install back to life.
I’m going to try to pick up the slack around here so posts like this don’t sit for 2 days however at this time I don’t know as much as I’d like to about the software.