If the messages were in white lettering on a black rectangular background, and in English, French, German and Japanese, then you almost certainly had what's known as a a 'kernel panic'. According to MacFormat magazine these are rare and often fixed by restarting. So don't worry, but check it out on the Apple support website if it happens again. Scary when it happens - once in 20+ years in my case - but usually a one-off event. You could also buy MacFormat December 2009 issue and read page 37.

Bill