Issues with working with BlockUI Plugins

Issues with working with BlockUI Plugins

Hi , I am using jQuery blockUI plugin * Version 2.33 and jQuery v1.4.2

Now when i am using the statement
$(document).ajaxStart($.blockUI).ajaxStop($.unblockUI); , it is working good

but as soon i want to pass my custom option like below :
$.blockUI({ message: '<h1><img src="busy.gif" /> Just a moment...</h1>' }); , it is NOT working and says

In Internet Explorer (version 8) it say : 'handler' is null or not an object
In Firefox version 3.6.8 it say : d is undefined


Please help me to figure out what went wrong, i have seen the demo pages from the official site and it  was working both on FF and IE , i am not sure what version of jQuery they are using. The plugin is exceptionally very good , so please please help me to use it.

Thanks in Advance
Sachin Srivastava