Im using fedora 16, somehow i wanted to change the look of fedora
followed the instruction from this SITE

according to the instruction. I need to place the new theme in /usr/share/gnome-shell/ and the theme works, it instantly changed the look of my desktop.

but when i restarted, the moment fedora boots it shows me this error "Oh no something has gone wrong!"

http://estrip.org/content/users/tiny...117_083221.jpg

then, I rebooted and went to recovery mode
went inside /usr/share/gnome-shell deleted the theme and brought back the default one.

have you experienced this? what can i do to use the new themes without getting the errors when i restart?

Instead of going through all that why don't you just install gnome-tweak-tool and use it to install themes? Why are you deleting or renaming native gnome folders/files without knowing what can happen? Much better to use the native tools and after becoming comfortable with them read the man pages and learn to do things manually.