PreLoader Tutorial Gives the info needed
A couple of things didn't work as said, but that's because you made it with 5, and I'm using MX, so I won't penalize you for that. Just one thing that was different that I couldn't figure out on my own: for the textbox varible name, I couldn't find any place to set it in MX. As a result, the percent thing always stays at 0.
One more thing, you can only tween between 2 keyframes. You can make 1 keyframe, then insert regular frames down to 100 and tween that. Also, the tweening wouldn't work because the objects were ungrouped. Don't know how this will affect the actual preloader progress bar, but something tells me that it won't work properly