Does anyone here have a clue why on one of my servers, the feature to download a home directory backup doesnt work?

This is using both vertex and Xskin themes, the link is correct in the html
Code:
<a href="<cpanel Cgi="backuplink()">">Download a home directory Backup</a>
But all it does on this 1 server is download an empty tar ball.. no matter what account I go into.

On my other servers, using the same WHM/Cpanel, (CP6.4.2 S75) it works perfectly normally.

Any clues?

cPanel.net Support Ticket Number: