Hudson having problem with Subversion: hudson.model.Job.hasCascadingProject()Z

One day, a few of our Hudson jobs (but not all) started to have this error when executing.

FATAL: hudson.model.Job.hasCascadingProject()Z
java.lang.NoSuchMethodError: hudson.model.Job.hasCascadingProject()Z
 at hudson.scm.PerJobCredentialStore.getXmlFile(PerJobCredentialStore.java:137)
 at hudson.scm.PerJobCredentialStore.<init>(PerJobCredentialStore.java:58)
 at hudson.scm.SubversionSCM$DescriptorImpl.createAuthenticationProvider(SubversionSCM.java:1820)
 at hudson.scm.SubversionSCM$DescriptorImpl.getRepository(SubversionSCM.java:2069)
 at hudson.scm.SubversionSCM$DescriptorImpl.checkRepositoryPath(SubversionSCM.java:2039)
 at hudson.scm.SubversionSCM.repositoryLocationsNoLongerExist(SubversionSCM.java:2272)
 at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:748)
 at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:711)
 at hudson.model.AbstractProject.checkout(AbstractProject.java:1229)
 at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:507)
 at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:424)
 at hudson.model.Run.run(Run.java:1367)
 at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
 at hudson.model.ResourceController.execute(ResourceController.java:88)
 at hudson.model.Executor.run(Executor.java:145)

This turns out to be at the Subversion check-out step:

You can click on "Update credentials" to go to a screen to enter in your credentials.  But you might get the following error:

HTTP ERROR 500

Problem accessing /hudson/job/PWS-OCDT/descriptorByName/hudson.scm.SubversionSCM/postCredential. Reason:

    hudson.model.Job.hasCascadingProject()Z

Caused by:

java.lang.NoSuchMethodError: hudson.model.Job.hasCascadingProject()Z
 at hudson.scm.PerJobCredentialStore.getXmlFile(PerJobCredentialStore.java:137)

At this point, check the file-system of your Hudson server.  Under <HUDSON_HOME>\jobs\<Job name> you may notice that compared to Jobs that are working, the problematic job does not have a "subversion.credentials" file.  Copy over this file as-is to the directory.  No Hudson re-start is necessary; just go back to the Dashboard and choose the problematic Job.  From this point, you should be able to choose "Update credentials" and work through the screens without getting an unhelpful

hudson.model.Job.hasCascadingProject()Z 

error.  FYI, this is Hudson ver. 2.1.2 and our Subversion server location changed, which may have caused this issue.