You are probably running into a file permissions limitation. In Linux, your regular user account is not allowed to mess with certain areas. If you are sure you want to do something in those areas you need to do it as root. You need to install a promgram called "rootsh". That program will allow you to become root when needed. Once installed enter this command to become root:

sudo gainroot

Now you have all the power to do whatever you want. Even completely destroy your installation. So, be very careful. Twice.