CSS and IE5 for Mac

I'm trying to get a quite complicated style sheet to work on IE 5 for Mac. Unfortunately, it needs to run on 5 or 5.1 and not 5.2 (where it works fine) as the organisation where I work has yet to upgrade the Mac browsers!!

The odd thing is that if I test it locally it works fine but once I try to test it on the server, it displays a blank page. I've tried it on 3 different servers.

I will try to simplify the style sheet and see if it has an effect but this isn't really a solution as it will mean changing the design.

The same thing seems to happen with Opera 6 for Mac and Windows (judging by the screen grabs from BrowserCam). I've used @import to hide the stylesheet from older browsers.

If anyone has come across this problem or if you can shed any light on why, I'd really appreciate the help.

Just discovered that if I don't use @import, the page displays fine in IE5 for Mac.
But this throws up another problem, how do I then hide it from 4 browsers - I thought all 5 browsers and later understood the @import command but obvioulsy not on a Mac?