Sorry that's me out of ideas at the moment. I'll do some searching and see if I can come up with a solution and post back if I find one.
I have just tried it in Firefox browser and it works OK so this would suggest as Ray has said, it is a problem with IE9. You could, until a fix is found, download Firefox and use that to access your BTYahoo account.
Firefox is a very good browser and you should have no problems using it.
See link for Firefox download
Try Firefox meantime, I'll post back if I find out what's happening or hopefully somebody else has had this problem and already knows the fix.
I am not sure why it would only be happening with the BTYahoo site unless it is a script problem with the site. I don't think this will sort it but is worth a try and that is to reset Internet Explorer, you can do this by:
· Close any Internet Explorer windows
· Click Start
· Click Control Panel
· Open Internet Options (you may have to switch from category view to icons to find this)
· Click the Advanced tab
· Click Reset…
· Click Reset
· Click Close
· Click OK
· Open Internet Explorer
Try printing email now.