Searching for packages results in an internal server error on RHN Satellite 5.1, 5.2, or 5.3

Issue

• Internal Server Error when searching for a package via Satellite web UI

• Exception stacktrace like the following in Tomcat logs (/var/log/tomcat5/catalina.out):

  Caused by:
  java.lang.NullPointerException
          at
  com.redhat.rhn.frontend.action.channel.PackageSearchAction.performSearch(PackageSearchAction.java:286)
          at
  com.redhat.rhn.frontend.action.channel.PackageSearchAction.setupForm(PackageSearchAction.java:213)
          at
  com.redhat.rhn.frontend.action.channel.PackageSearchAction.execute(PackageSearchAction.java:89)
          at
  org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
          ... 40 more