Well, assuming you've got execution permissions and aren't chrooted by the admins, then you should just be able to build a php script to run the find command for you, assuming they have find installed.
<?
find libgd.so;
?>
Note that those are back ticks, from the upper left side if the keyboard, under the ~ key, not the single forward tick ' from the bottom of the " key. (on us keyboards, ymmv with intl keyboards)
