Ok, there was a bug in v1.5 that has the symptoms you describe, but it only effected UK TiVo's.

So, back to your original problem...you say it's not starting TWP. Did you install TWP yourself? or do you mean TiVoWeb that comes standard on the image.

Also have you edited rc.sysinit.author on a PC? this will add dos characters to the file stopping it from executing.

Peter.