Mozilla Firefox

The Firefox page opens but I cannot surf the web. I am running windows EP with McAfee virus protection. The computer has other users that have no problem acessing Firefox I am the administrater and cannot asccess it.Here is the ALERT Message that I am getting. Help

Could not initialize the application's security component. The most likely cause is problems with files in your application's profile directory. Please check that this directory has no read/write restrictions and your hard disk is not full or close to full. It is recommended that you exit the application and fix the problem. If you continue to use this session, you might see incorrect application behaviour when accessing security features.