As a first thing could you please try restarting your computer and then try to launch the game again? If this does not help, please go to www.swtor.com/download, download the launcher setup file and run the setup over the current installation.
Please come back to us if the issue remains.
None of that worked. I tried doing it a few times too.
In order to fix it, I ended up having to reinstall the game(which took 9.5 hours) for a third time. Getting a bit tired of having to reinstall SWTOR after some bug forces me to close it or crashes it. It's a massive game and reinstalling is a really crappy fallback imo.