i get some error while opening any webinar , can any one say whats the problem




Warning: OCIStmtExecute: ORA-01400: cannot insert NULL into ("TEST"."MTGATTENDEESTATUS"."EMAIL") in /www/htdocs/mywebex-t20-localized_en-us/onstage/include/ociconnect.inc on line 170
This sql statement have errors:insert into MTGATTENDEESTATUS (SiteID,AID,ConfID,Email,UUID,JoinTime,LeaveTime,EVENTTYPE,USERNAME,REMOTEHOST,USERAGENT,RefNum1,RefNum2,RefStr1,RefStr2,RefTime1,RefTime2,Status) values (232935,2610342,317835569,'',0,TO_DATE('05/15/2006 09:33:21','mm/dd/YYYY hh24:mi:ss'),'','PlaybackOnstageJava',' ''','61.246.50.168','Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)','','','','','','',1)