Need simple mouseover image enlarge script figured out

This is simple, and I will pay $10 to the first person to figure it out. I need to have the mouseover image enlarge feature located at [login to view URL] (move your mouse over any of the thumbnails to see the image enlarge). I need this feature to work at [login to view URL] whenever you move your mouse over one of the thumbnails it should display the large version of the image (the same path and file name as the thumbnail but the file name start with an L instead of an S. I have already copied all the script and commands from the example site, but I can't seem to get it to work. The file is a PHP file, so I don't need you to actually fix it, just tell me what I am doing wrong an how I can fix it. The first person to give me instructions as to how to fix it gets selected as the winner and gets paid $10 via PayPal or GAF escrow (you choose). Price is non-negotiable. I need this done FAST. Thanks, George