Run into a strange issue today. Was setting up a new blog using the cpanel worpress add-on and everything was fine until I tried to login as admin into the backed. Sure enough the details were accepted, but instead of the dashboard I was greeted with this message:
You do not have sufficient permissions to access this page error.
After a bit of searching it seemed it could be a corrupt db, so I reinstalled, but the same thing happened. Then I had a hunch, this was the first time I was trying to setup a custom table prefix. Sure enough changing the prefix back to just “wp” in the installation form fixed it.
Must be something messed up in the install script or somewhere refers to the default prefix where it should use the custom one.