To find out if you've got agpgart, as root, type lsmod...
That will list all the currently loaded modules.
If agpgart is one of them, then nah, that's not it.
If it's not in there, try the command:
and see what you get.
Also, did you install the drivers with rpm?
Try uninstalling them, and then installing them with the force overwrite existing libraries function, don't remember which option that is. But it's a common problem switching from mesa to opengl.
HOpe this helps