Since /usr/share/skype is gone, and this is a systemwide folder created by installing Skype, that suggests reinstalling Skype might work. (Note that this will likely work even though resetting your user-specific Skype settings did not, as resetting your personal Skype settings doesn't affect anything in /usr.)

Assuming you installed Skype from the partner repository (for example, in the Software Center), running these commands in a Terminal (Ctrl+Alt+T) will reinstall it:

sudo apt-get update

sudo apt-get --purge --reinstall install skype skype-bin

[I've edited this to include purging and reinstalling the skype-bin support package as well, which may be necessary, as described in minerz029's excellent answer.]

Assuming all that's wrong is the missing /usr/share/skype folder, a weaker form of reinstalling (which doesn't clear out systemwide configuration files) can be achieved by leaving out the --purge flag or by going into the Software Center, removing Skype, and installing it again.

If you installed Skype in some other way, you should tell us how; depending on how you installed it, it may or may not be expected for a /usr/share/skype folder to exist, and the inaccessibility of those files could be a file ownership/permissions problem.