Problems installing Pycharm

Hello,
I have dowloaded Pycharm and untared the file:
tar xfz pycharm-*.tar.gz
Then I ran pycharm in the bin subdirectory:
tX220:~/pycharm-community-4.0.3/bin$ ./pycharm.sh   
Startup Error: Application cannot start in headless mode –

What is this error "Application cannot start in headless mode"?
Thanks