In your place I would use Odin to reflash* the stock rom and than reinstall the LauncherPro. It works great and didn't force close for me now (using it just a couple of days, but feels and acts way more stable. You can download it from the Market.
Before reflashing, you need to make sure that your downloading mode is operational.
Turn off your phone:
volume down (and hold)
home (and hold)
power button (and hold)
You should get the yellow android dude working on a stop sign or something. From there you plug it on your PC and work from there...
Problems with TWlauncher are frequent, so consider swapping
I'm doing this right now. The screen shows a yellow picture of an android doing shoveling "downloading....do not turn off target!!!". This has been almost 20 minutes. Is this normal? why is it taking too long to download??? Pls advise.