Description of problem:
In the RHEL6 Migration Guide it is stated (sec 2.2.2.5):

"The %packages, %post, %pre and %traceback sections must have an %end option at the end. Previously, these sections had no explicit ending token, but ended where another began. Starting in Red Hat Enterprise Linux 6, using %end is required. Files without an %end token will fail."

This does not appear to match reality; kickstarts that don't contain %end sections don't fail, but run correctly. They do, however, throw a deprecation warning. This is actually fortunate, since Satellite does not currently generate compliant kickstarts - see bug #641248 .