Problem: Many extensions on extensions.apple.com cannot be installed. However, extensions that I installed before, no problem, such as AdBlock, Bing, Echofon. Others, will not install, it will be stuck at installing. And Safari may lose response after a while. I initially noticed that if I try to install YouTube5 which I downloaded myself, Safari will immediately lose response. Tried solutions: - Reset Safari - Run OnyX - Repair disk permissions - Deleting all the extensions; extensions I installed before will install, others won't - Deleting Clicktoflash and Glims Still having the same problem. I feel desperate and helpless. Any ideas?