We have a web site with an ocx written in VB, inside a CAB on our
server.  The ocx loads just fine on most computers, but on some
computers we just get the little box with the X in it.  There is no
error message.  This is a site for paying customers.  It is always run
with IE6, Win 98 or higher, the site set as a trusted site in browser
security.  We have double checked all those things.  It sometimes
happens on a computer at the same location as another computer that
works fine, so that eliminates the possibility of any provider problem.

How would you start to track down a problem like this ?  What do you
think it might be ?