Try pulling the battery and leaving it out for a minute or two. When you restart the phone let it run for a few minutes. If you get a force close error again on TW, just let it sit for a few minutes. It may work through it.
I had that error once, it kept FC looping in TWLauncher. I can't remember what I did to get it to stop.
Since you have root access, if you can get it stable and booted up, one thing you can do is download Titanium Backup. Download ADW Launcher, GO Launcher, or Launcher Pro Plus, and use one of them as your homescreens. Then go into Titanium Backup and "freeze" TW launcher rather than uninstall it.
Uninstalling system apps like TW Launcher can create more problems than it solves. "Freezing" them in TB prevents the system from running them, but doesn't make the phone unstable.
I froze my TW launcher (I use LP Plus) and haven't had the FC loop issue since.
As far as how you got there...what have you done to the phone since you rooted? Uninstalled bloatware? Installed custom ROMs or kernels? Anything you can tell us will help with diagnosis.