iframe going crazy in IE

[benbroad]

I have a site we are developing for a client that has a nested iframe - no way round it Im afraid, it's the only way to get it to do what the client wants. Now when I load a new page into the inner iframe it goes a bit nuts in IE. Its fine in firefox. I have linked to screenshots of it as words cant describe how badly IE mangles it...

What it should look like (http://www.ninefortynine.com/temp/PS_ok.jpg)
What IE does to it (http://www.ninefortynine.com/temp/PS_broken.jpg)

If anyone has any ideas I would really appreciate it!

Ben.

[benbroad]

Quick update... It only seems to do it on some machines. I have a laptop running IE 6.0.29 which works fine, but the exact same IE version running on my de4stkop PC messes it up. Very, very odd.