TO THOSE OF YOU WITH CONTACT PROBLEMS: if you're rooted/freezing bloatware, DON'T freez the yahoo authenticator app, for whatever reason, this seems to really mess with the contacts app
FOR THOSE OF YOU WITH THE 7 ERROR WHILE TRYING TO INSTAL: I found that what gave me this error was the fact that I had installed Bootstrap Recovery while running rooted froyo. SBFing your phone will not get rid of this on it's own. you can follow these stops to ensure that Bootstrap Recovery is completely removed from your device:
1. Reroot
2. Get root explorer in the market
3. Uninstall the bootstrap
app
4. Go into root explorer to system/bin
5. In top right corner tap r/w
6. Delete the file called hijack
7. Delete logwrapper
8. Rename logwrapper.bin to just logwrapper
9. Reboot and it should be gone.
After this, you can unroot and instal the leaked unrooted GB (which I did and rooted with one click - worked seamlessly) or try rooting and installing the prerooted GB, but that would involve reinstalling Bootstrap and I never got this method to work..
These may not be your problems, but these are the solutions I found to the same problems you all seem to be having, hope I was of help