I can create a Jenkins job with multijob in postbuildscript the first time. However, if I go back to make changes to the job the second time, then it does not allow me to save the job configuration (Screen Shot-postbuildscript-multijob.png).

Clicking "Save" does nothing.

Clicking "Apply" pops up an empty Error windows (Screen Shot-postbuildscript-multijob-apply.png).

XML generated for the Jenkins job is shown in postbuildscript-multijob-jenkins-job-ABC-xml.txt.