firefox stopped working after 5.01 update

i have a MacBook Pro (13in Mid 2010)

APP store reflected an update to MAVERICK (DIGITAL CAMERA RAW COMPATABILITY UPDATE 5.01).

went ahead and updated it.

tried to use FIREFOX as web browser (like i do everyday) off of my Dock.....icon does not bounce to show that its starting and will not start. went through launch pad and the error message i get is The application "FIREFOX" can't be opened -600"

tried Safari a few times and it looked like it was working and then would just stop and go back to the desktop. same with the APP store. it would look like it was about to start (would show the page loading) and then go back to desktop).

tried Safar and APP store again and then they started to work (this is being posted via SAFARI).

any idea WHY this is happening?

nothing has changed.....other than the recent update (11/12).......

relatively novice APPLE user.....(i am slowly coming around).....any help/advice would be appreciated.