Eric,
Another thing to check with your client is how they have their permissions set.
Safari has a slightly different security tab than other browsers and under security there are several check boxes for "web content" Of them, there are three that would be critical for the content to show and those would be:
Enable Plug-Ins
Enable Java
Enable JavaScript
If one of those was not checked, that would probably keep it from rendering correctly.
Regards,
Brian