I had this problem with a blog, I managed to fix it.
I installed on a server which I ran many other wordpress blogs, all 2.6.3.
I tried all the different fixes and none worked for me.
I switched my PHP version 5 to version 4 in the settings, in my webserver control panel.
This seemed to help, the wordpress install screen loaded but I also got a new error message at the bottom. Which I used this to fix before I continued; link
I hope this helps someone.