Yesterday I set out to get YouTube application to work, now that I have upgraded to 3.0. I found a tutorial that stated that I should delete the /private/var/root/Library/Lockdown folder. I was so eager to get going that I didn't read the full instructions that said to do it after I had made a backup. Afterwards YouTube application worked, but after a restart the phone was locked and only emergency call was allowed. This repaired itself when I connected it to my PC at work, to which I had made backups earlier. The bad part is that now no 3rd party applications will start. I have restored the phone several times, but still no 3rd party apps will start.

What should I do?

Should I jailbreak and delete Lockdown folder again, but this time connect it to my Mac at home which is the one that I used first? Could the application authorization mechanism be tied to it, even though my office PCs iTunes is authenticated with my Apple-account?