It's not fixed at the URL you posted above. The path is currently set to
If the script was in a folder named "js" in the folder named "construction", the path would be correct, but it's not.
Firebug has two easy ways of showing whether a script is linked correctly. In the Scripts tab, clicking on the name of the parent file in the bar below reveals a drop-down menu listing the active scripts. Also, in the HTML tab, if you click the triangle to the left of a script element it will show the script code. The script for fancyplayer.js shows the code of your server's 404 error page, so the script file has not been found.