This has happened to me a few times, and it keeps catching me out because I rarely use Outlook Web Access on my computer at home (MacBookPro, OS 10.4.11). If I have started OWA on IE6 (in a Win98 bottle) and am viewing one of the emails (which are opened in a new window) AND if I (carelessly) use the Cmd-C shortcut for copy (instead of the menu Edit | Copy), the IE crashes and restarts. I have submitted a ticket regarding this.
Incidentally - I also notice that the buttons in OWA are not responsive immediately - I have to click them once to select and then a second time to activate them, which is rather strange (for example the Send button).