Cannot copy from office 2007 in FF3 version 3.0.3

Hi, I'm a newbie. I'm using FCK (6.x-1.3-rc3) for my website. It's beautiful but I have a problem as I say in title

I have a .docx (read with MS office 2007) so I want to copy it to my website (read with FF3 version 3.0.3). But when I copy it's contents to body of a node -> save -> then my node display a series of XML

But when I read my website by IE6, my problem has gone.

Can you guide me plz ????

Thx a lot