jquery-1.4.2.min.js Exception thrown and not caught

jquery-1.4.2.min.js Exception thrown and not caught

Hi,
I was using jquery-1.3.2.min.js to show a modal dialog on a button click event handler and this worked fine.
 
The same did not work with jquery-1.4.2.min.js and yielded the following script error on my IE -8 broswer.
 
Message: Exception thrown and not caught Line: 75 Char: 399
 
Could somebody help me on this please!
Durga B