i think you should update your flash player.. try it

Which Firefox has this problem: Android or Windows? For Android, Adobe's really not supporting Flash any more, so it is what it is. For Windows, there are many possible reasons for the problem. This is some standard guidance that addresses the most common issues with the Flash Player plugin. I'm sure you've seen some of it before, but just in case: (1) If you have any recorders/downloaders that interact with Flash media make sure they are as up-to-date as possible, or disable them temporarily. (2) Disable hardware acceleration in Firefox and in Flash (A) In Firefox, un-check the box here: "3-bar" menu button (or Tools menu) > Options > Advanced > General > "Use hardware acceleration when available" That takes effect the next time you exit and start Firefox up again. (B) In Flash, right-click the media and choose Settings, then the first mini-tab and uncheck the box to use hardware acceleration. More information in this support article from Adobe: http://helpx.adobe.com/flash-player/kb/video-playback-issues.html#main_Solve_video_playback_issues (3) Disable protected mode (Windows Vista and higher) The protected mode feature of the Flash player plugin has security benefits, but seems to have compatibility issues on some systems. You can disable it by creating or editing a settings file. The following pages/posts provide different approaches for that: * Adobe support article under the heading "Last Resort": [http://forums.adobe.com/message/4468493#TemporaryWorkaround Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?] * Manual steps: https://support.mozilla.org/questions/968190?page=5#answer-509209 * Batch file to automate the manual steps: https://support.mozilla.org/questions/982093#answer-518078 (alternate version of Carm's batch file with a few changes by me: [https://onedrive.live.com/?cid=f7d304d92388737d&id=F7D304D92388737D!336&ithint=file,.bat&authkey=!AP2FXW2Y_3BXZyo]) Flash needs to completely unload from memory (exiting and starting Firefox up again might help) before this takes effect. Any improvement?