To fix youtube loading error on squid lusca, we need to modify the storeurl.pl file. Here is the fix by Syed Jahanzaib, http://aacable.wordpress.com/2012/01/30/youtube-caching-problem-an-error-occured-please-try-again-later-solved/
Make sure to chmod +x, and chown the user and group of your squid. Mine is proxy, others maybe squid.