I just noticed your edit to your earlier post listing various nautilus related packages you had installed. This makes me think you should look for other packages that should be installed but aren't. The nautilus-whatever packages you list will have nautilus as a dependency. So if you were to ask for one of them to be installed and nautilus wasn't already installed, nautilus would get installed. That they were installed and nautilus wasn't means your dependencies were broken. Which is Bad. That situation should not have occurred.
I'm afraid I don't actually know how you go about verifying dependencies on Red Hat. on SuSE distros you can use 'zypper verify' which will check that all dependencies for all packages installed are actually installed. The closest I can see for Red Hat is 'yum deplist'. But I'm not convinced that's equivalent.
One trick that should work to make sure you have all dependencies for a package installed would be to forcefully remove it then ask yum to install it again.
$ rpm -e --nodeps nautilus-extensions
$ yum install nautilus-extensions
You obviously can't do that for every package though.