Here's how to fix YouTube after ZiPhone jailbreak/activation/unlock
1. Download these zip files & unzip>>>
http://soundsgood.cocolog-nifty.com/...es/youtube.zip
2. SSH to your iPhone (WinSCP or Independence)
Put the files you have downloaded to>>>
/var/root/Library/Lockdown
replacing the existing with your downloaded files
3. In your lockdown folder you will see an "activation" record folder.
DELETE any files in that folder.
4. Exit out of SSH and reboot your iPhone.
You should now have a working YouTube program
GOODLUCK