He survived, although the video you're thinking of wasn't Mark Webber, I am not sure who it was, but he survived the crash. That was a damaging aerodynamic flaw for the MB CLR team, and these crazy backflips occured three times for them at LeMans. Here's a good writeup (and good LM site) that goes into more detail about the flaws of this, and the Porsche GT1, which had a similar crash at Petit-LeMans.
Webber's morning warm-up incident, Le Mans 1999: