fix problems going on/offline w/o an unsent messages folder r=cavin, sr=sspitzer 158969

mailnews/base/resources/content/mail-offline.js

@@ -56,6 +56,8 @@ function GetMailOfflinePrefs()
 
 // Check for unsent messages
 function CheckForUnsentMessages()
+{
+  try
   {
     var am = Components.classes["@mozilla.org/messenger/account-manager;1"]
                  .getService(Components.interfaces.nsIMsgAccountManager);
@@ -76,6 +78,9 @@ function CheckForUnsentMessages()
         }
       } 
     }
+  }
+  catch(ex) {
+  }
   return false;
 }