Problems after QuickTime 7.7 update

After the 7.7 update, I keep getting "The movie could not be opened", "An invalid public movie atom was found in the movie." All my .mov files will not open, and I cant import them in final cut. Before the update everything was working fine, I could open those files in QuickTime and could import and use them in Final Cut Pro. I'm devasted as to how to fix this. Couldn't find anything online about how to fix this.