The _version_ error message is missing a space between _version_ and “field”:
Oct 28, 2012 10:24:34 AM org.apache.solr.update.UpdateLog init SEVERE: Unable to use updateLog: _version_field must exist in schema, using indexed="true" stored="true" and multiValued="false" (_version_ does not exist) This is in 4.0.0. -- Jack Krupansky
