Package installation fails with "error: failed dependencies"

Issue

• Package installation fails with "error: failed dependencies", for example:

  error: Failed dependencies:
          hal >= 0.5.8.1-52 is needed by rhn-client-tools-0.4.20-33.el5.noarch
          python-dmidecode is needed by rhn-client-tools-0.4.20-33.el5.noarch
          rhnlib >= 2.2.7 is needed by rhn-client-tools-0.4.20-33.el5.noarch