FF uses TigerStyle Theme | IE uses default

Any idea why this could be happening?

When I log into my Admin with Firefox, the dashboard uses the TigerStyle Administration theme, whereas in IE it uses the default style that comes with 2.5.1.

This happens on two completely separate computers(different buildings!).

I’ve done the classic ‘Clear Private Data’ to death and it doesn’t seem to affect it, and it’s obviously pretty frustrating.

Any ideas?