After upgrading Hudson, all of my jobs that had Release builds failed to load. I see the following message in the log:

Dec 11, 2009 12:11:53 PM hudson.model.Hudson$4 onTaskFailed
SEVERE: Failed Loading job test release build
java.lang.AssertionError: class hudson.plugins.release.ReleaseWrapper is missing its descriptor
at hudson.model.Hudson.getDescriptorOrDie(Hudson.java:900)
at hudson.tasks.BuildWrapper.getDescriptor(BuildWrapper.java:194)
at hudson.model.Descriptor.toMap(Descriptor.java:595)
at hudson.util.DescribableList.toMap(DescribableList.java:120)
at hudson.model.Project.getBuildWrappers(Project.java:117)
at hudson.model.Project.updateTransientActions(Project.java:220)
at hudson.model.AbstractProject.onLoad(AbstractProject.java:223)
at hudson.model.Project.onLoad(Project.java:86)
at hudson.model.Items.load(Items.java:107)
at hudson.model.Hudson$12.run(Hudson.java:2091)
er.java:146)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
at hudson.model.Hudson$3.runTask(Hudson.java:642)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
java:1110)
.java:603)
at java.lang.Thread.run(Thread.java:636)

I can't access any of these jobs through the Hudson web interface. Is there anything I can do to recover?