Why does my Satellite upgrade from 5.5 to 5.6 error out over 'cobbler2' dependencies?

Issue

• With a Red Hat Enterprise Linux 5 installation as base, and Satellite 5.5 installed on that, upgrading to Satellite 5.6 was causing a problem with an error such as this:

---> Package cobbler-loaders.noarch 0:1.0.2-2.1.el5sat set to be updated
--> Processing Dependency: cobbler2 for package: cobbler-loaders
---> Package perl-Socket6.x86_64 0:0.19-3.fc6 set to be updated
---> Package postgresql84-libs.x86_64 0:8.4.18-1.el5_10 set to be updated
---> Package spacewalk-common.noarch 0:2.0.1-3.el5sat set to be updated
--> Processing Dependency: cobbler2 for package: spacewalk-common
--> Finished Dependency Resolution
spacewalk-common-2.0.1-3.el5sat.noarch from red-hat-satellite has depsolving problems
  --> Missing Dependency: cobbler2 is needed by package spacewalk-common-2.0.1-3.el5sat.noarch (red-hat-satellite)
cobbler-loaders-1.0.2-2.1.el5sat.noarch from red-hat-satellite has depsolving problems
  --> Missing Dependency: cobbler2 is needed by package cobbler-loaders-1.0.2-2.1.el5sat.noarch (red-hat-satellite)
Error: Missing Dependency: cobbler2 is needed by package spacewalk-common-2.0.1-3.el5sat.noarch (red-hat-satellite)
Error: Missing Dependency: cobbler2 is needed by package cobbler-loaders-1.0.2-2.1.el5sat.noarch (red-hat-satellite)
 You could try using --skip-broken to work around the problem
 You could try running: package-cleanup --problems
                        package-cleanup --dupes
                        rpm -Va --nofiles --nodigest