Runtime error while using hotmail

The strangest thing is happening to me while using my hotmail. Whenever I try to send mail with an attachment, or forward an email, I get a message box saying "Runtime error, error: 'g_state.bgColor' is null or not an object." Now this only happens when I use hotmail. If I try the same thing using yahoo, I have no problems. Can anyone help me please because I use my hotmail a lot more than my yahoo