Adobe Shockwave for Director Netscape plug-in issue in Firefox

I was watching a video in YouTube when plug-in errors occurred. I checked if my plug-ins need updating, but Firefox tells me that Adobe Shockwave for Director Netscape plug-in with Version 11.5 was already outdated. I tried to update it few times. I then restarted the browser and even the PC, but it keeps on telling me that it is out of date. Please advise me on what other steps I need to do.
Thank you.
