[SOVLED]"E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages."

Platform:
                  Ubuntu 11.10(or other releases, not sure)
Diagnosis:
                 A "Forbidden" sign shown at the notification center, with an error message "E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages."

Reason:
                Some package installed have unmet dependencies.
Solution:
                sudo apt-get dist-upgrade
                Command above gives you the information that which package(s) are problematic.
                sudo apt-get remove problematic_package(s)