Probably you want to UnRoot right? Just reinstall the GingerBreak, click on UnRoot e then delete the app.
I have the exact same problem.
Looking for answer.
I fixed it by getting the older buid otasigcheck.sh and puting it into the newer build zip. The older file is about 900B and the new one is like 2.2KB. You should try that....
I think you can't move the entire app to SD, even with darktremor's a2sd, the app still having some "parts" on the SD...
You can clear Dalvik Cache with Titanium Backup as well you can remove bloatware and backup yous apps and settings.
Doesn't z4root work on a different exploit? Are you sure that using it to unroot will work?
Sent from my LG-P500 using XDA App
Gingerbreak was updated to v1.2, now it supports UnRoot.