movie not loading in html browser???

hey guys,
i have recently taken over a flash based site for a company that had their in-house designer create and program the site.

here is how the site functions:
• MAIN.swf is loaded into INDEX.html
• when user clicks on a section tabs, SECTION1.swf is loaded into EMPTY_mc inside of MAIN.swf.

when i test the site locally, everything works just fine. but when i post it online, only MAIN.swf loads fine. once a section tab is selected, the SECTION1.swf does not load. now i am only having this problem on Safari & Firefox. IE seems to works just fine but the others wont. i have contacted their designer and he has stated that i should check the AC_FL_RunContent javascript. does anybody know what exactly i should be looking for?

thanks in advance