Try doing a prebinding update. Type this into the terminal and enter your root password when prompted:
sudo update_prebinding -root / -force
Just like that. Should take a while to run and re-prebind stuff... then, restart immediately after doing that. Make sure you run that without any other programs running. It sounds like your applications aren't linking to the right libraries/application files...
So, try this... restart your machine. Log in with the shift key held down... this will prevent anything in your login items from starting. Launch the terminal. Type that command in the terminal and let it run. When it's done, quit the terminal and restart one more time. That should take care of it! If it doesn't, let us know!