Where is System Events?

I downloaded MainMenu which I guess helps clean up my computer a bit.

I repaired disk permissions and cleaned out the user and system caches. After this it recommended I reboot the computer so it did so for me. The computer restarted and the first thing on the screen (still up) is asking "where is system events?" with a list of Apps for me to choose.

Any help? lol.

I'm befuddled on the situation and could really use some help.