Why did Aerosmith and ZZ Top cancel their concert in Hershey, PA tonight? Is it because of Michael Jackson?

yeah, i was supposed to be at the show in Cincinnati on wednesday and we showed up to the place and it was canceled. We drove 6 hrs to see them too... we still dont know why and have been looking on aeroforceone.com. they don't say anything but that an artist had an injury. i already knew that brad was gonna be gone because of his concussion, but yeah, this was sudden, and the truck drivers didn't even know about it. haha, i bet they are still in Ohio lol. but hey, if you hear anything, please email me at gypsymatt@gmail.com. hope to figure this out soon, and hope everyone is ok. peace