Problem when starting PPCS6

Hi,

Yesterday when I worked on PPCS6, everything was fine. Today, when I've tried to open the software, it begun normally but after, instead of showing me the window where I select the project, it stops and I have that :

It's not the first time that it happens, but normally I just had to restart the computer and everything works fine again but not this time..

Thanks

Computer :

Imac mid 2011

4 GB - AMD Radeon 6750M 512 MB