What do i do to fix this error?

I'm using the MATLAB program for the BEST Robotics competition and i'm having a problem when i try to generate the code. when i double click on GENERATE CODE it will start building in Easy C but then i get this error.

          Error due to multiple causes
-->Error evaluating 'OpenFcn' callback of Subsystem
           block (mask) 'RebTeks/'.
-->There is no application associated with the given file
               name extension.

I even opened an example model and click GENERATE CODE and I got the same exact error. I have no clue what the problem is....