mod_rewrite

[eluser]Dam1an[/eluser]
Workaround:
Assuming you've done your links using the anchor function, you just need to checnge index_page in the config file to be 'index.php' and all your links will be back to normal

Solution:
If you know where mod_rewrite.c (or .so) is, you could maybe check if that file exists, and if so, have index_page to nothing, else having it to 'index.php'
This is of course assuming that its enabled if they have it, although I assume thats in your .htaccess file to include it