Tabbrowser Extensions is a pretty problematic extension; it does so much, that any little tweak often causes everything to break. I've switched over to a combination of 4 or 5 smaller extensions that handle the elements of TBE that I wanted. Or, there's a new one called Tab Mix, which tries to be all-in-one without the code problems of TBE.
If you let me know what you use in TBE, I can give some suggestions for extension replacements. Or, if you feel self-sufficient today, read the thread
Rebuilding TBE's featureset with other plugins, III - MozillaZine Forums.