...yeah this is new to me, I'm running the latest minefield build and some videos wouldn't run at all with either NS and/or AB+ (latest versions) enabled. In my case I had to disable both to get a video playing, as reported here:
https://bugzilla.mozilla.org/show_bug.cgi?id=604420#c46
https://bugzilla.mozilla.org/show_bug.cgi?id=606529#c3
Okay just wanted to mention it. The issue must be on FF side it seems.
flash player issues on FF4 with NS and AB+
flash player issues on FF4 with NS and AB+
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101022 Firefox/4.0b8pre
Re: flash player issues on FF4 with NS and AB+
okay this is fixed with the latest update.
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101023 Firefox/4.0b8pre