2D to 3D in photoshop CS4 extended

I am unable to use the 3D category from the main menu in CS4 extended. The commands in that category are grayed out whatever I try. If I open a 2D image how do I convert it to 3D?

Poke around here

<http://www.russellbrown.com/tips_tech.html>

just stay away from the purple acid, man

thanks for this response