BlackBerry is on their A game by pushing out updates for the recently released iPhone and Android BBM. BlackBerry has rolled yet another update to BBM for iPhone with version 126.96.36.199.
The update fixes the contacts crash and a slew of others. There is a feedback section in the options for iPhone BBM in case you spot anymore bugs and want to notify BlackBerry.
The update should be automatic, otherwise you can get it from the Apple app store here.