I’m sorry, I’m no php expert and I just got this wordpress thing working so I doubt I’ll be of much help. Did you read my previous post before yours? That was how I solved my problem. Other than that I dunno. Did you double check all your db settings and make sure your host supports the minimun reqs for wordpress?
I ran into the same problem as you and I out that I input the db connection details in the wrong area. On the wp-config.php file, where it says “define(‘DB_NAME’, ‘wordpress’); ” I put my username where it says DB_NAME instead of where is says wordpress. I did that same thing with all of the fields and I got the same error message as you. Once I changed that, I installed it correcly. Hope this helps.