Just upgraded Firefox from 3.6 to 4.0. Now I cannot access my Lotus Domino Web Mail. A message about a Java Console error appears though, and the java log is as follows: Domino Release 8.5.2 (Windows NT/Intel) $HaikuForm - 401 Mozilla/5.0 (Windows NT 5.1; rv:2.0) Gecko/20100101 Firefox/4.0 03/24/2011 09:08:53AM A problem has occurred which may have caused the current operation to fail. 03/24/2011 09:08:53AM uncaught exception: [Exception... "Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMHTMLDocument.createElementNS]" nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)" location: "JS frame :: http://home.starbaseinc.com/iNotes/Forms85.nsf/iNotes/Proxy/?OpenDocument&Form=l_StdPageOperations_Gecko&l=en&gz&CR&MX&TS=20100811T081528,46Z&charset=ISO-8859-1&PresetFields=s_FullmailView;1,s_FullListViewVirtual;1,s_mailView;1,s_Base;1,s_FullInit;1,s_Sametime;1 :: CyB :: line 15" data: no] 03/24/2011 09:08:53AM : 0 03/24/2011 09:09:02AM A problem has occurred which may have caused the current operation to fail. 03/24/2011 09:09:02AM uncaught exception: [Exception... "Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMHTMLDocument.createElementNS]" nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)" location: "JS frame :: http://home.starbaseinc.com/iNotes/Forms85.nsf/iNotes/Proxy/?OpenDocument&Form=l_StdPageOperations_Gecko&l=en&gz&CR&MX&TS=20100811T081528,46Z&charset=ISO-8859-1&PresetFields=s_FullmailView;1,s_FullListViewVirtual;1,s_mailView;1,s_Base;1,s_FullInit;1,s_Sametime;1 :: CyB :: line 15" data: no] 03/24/2011 09:09:02AM : 0 This did not happen before I can't really give you a url since this is a secure site.