Duplicate mc

Hi,

I am facing a problem with duplicating movie clips. I looked at the tutorial that was pasted on this site and it works fine as long as I use the file that is provided for download in the tutorial. But if I create a file of my own then it does not work. It duplicates the file alright but when it duplicates, it removes the earlier one. Please help. I am using the same code that is provided in the tutorial. What am I doing wrong, my movie clip instance names are the same as the ones provided in the tutorial. P.S. I am using Flash MX 2004, is this why the duplicate movie clip function does not work. Do I need to write the function in a different way. If so, can someone show me how?

http://www.kirupa.com/developer/actionscript/duplicate.htm

Regards,
Vazash.