Fatal error: Uncaught exception 'Exception' with message '"400" Status: Bad RequestApache Tomcat/6.0.18 - Error report

HTTP Status 400 - org.apache.lucene.queryParser.ParseException: Cannot parse 'author:': Encountered "<EOF>" at line 1, column 7. Was expecting one of: "(" ... "*" ... <QUOTED> ... <TERM> ... <PREF in /data/www/content/includes/solr.inc on line 258