Some computers won't play my site, flash player 8 installed though

Hello everyone,

I’ve built a flash site in flash mx and it all works fine on most computers, but at my brothers work (for whom the website is for), there’s not a single computer that seems to play the site properly. They’ve got flash mx 2004 and flash player 8 is installed and use internet explorer 6.

The site opens with this language swf, where you can choose your language. After that it links properly to the main site, which displays well. Only thing is that none of the buttons works… So they’re basically stuck on the mainpage.
On other computers this problem doesn’t occur. All buttons work fine.

I can’t seem to figure out what the problem is. Can someone help me out please?
Thanks alot.