As mentioned by Omer on the list, there was still a missing conversion for Sakai 2.8
http://collab.sakaiproject.org/pipermail/sakai-dev/2012-January/015218.html
update poll_poll set poll_is_public = 0 where poll_is_public is null

Ideally this should have been in the 2.8.2 conversion script. I'm going to put it in the 2.8.3 conversion script so it's captured somewhere.

org.sakaiproject.portal.api.PortalHandlerException: uk.org.ponder.util.UniversalRuntimeException: Error invoking init method handle on bean rootHandlerBean
--> Error handling request
--> Null value was assigned to a property of primitive type setter of org.sakaiproject.poll.model.Poll.isPublic; nested exception is org.hibernate.PropertyAccessException: Null value was assigned to a property of primitive type setter of org.sakaiproject.poll.model.Poll.isPublic
at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:862)
caused by: uk.org.ponder.util.UniversalRuntimeException: Error invoking init method handle on bean rootHandlerBean
--> Error handling request
--> Null value was assigned to a property of primitive type setter of org.sakaiproject.poll.model.Poll.isPublic; nested exception is org.hibernate.PropertyAccessException: Null value was assigned to a property of primitive type setter of org.sakaiproject.poll.model.Poll.isPublic