Fixed loadMissedMessages parameter check

server/methods/loadMissedMessages.coffee

@@ -2,7 +2,7 @@ Meteor.methods
 	loadMissedMessages: (rid, start) ->
 
 		check rid, String
-		check start, Number
+		check start, Date
 
 		if not Meteor.userId()
 			throw new Meteor.Error 'error-invalid-user', 'Invalid user', { method: 'loadMissedMessages' }