Could you try some of the other suggestions in this article related to protected mode and hardware acceleration: [[Adobe Flash plugin has crashed - Prevent it from happening again]].

Crashes or other problems with certain multimedia content in Firefox (such as Flash videos, animations or games) can often be resolved by performing the steps in these Knowledge Base articles: * [[Flash Plugin - Keep it up to date and troubleshoot problems]] * [[Adobe Flash plugin has crashed - Prevent it from happening again]] <!--Please also note that html5 may need to be enabled to view some videos on youtube [https://www.youtube.com/html5]--> Please tell us if this helped!