Flash player doesn't install in Firefox

Flash wasn't working for me in Firefox. At one point, I had installed several flash players via Symantic or Adept, until learning I should only install flashplayer-nonfree. I removed the other ones, but still no go. I tried downloading the package from Adobe manually, and installing via the command line, but got this error:

Please enter the installation path of the Mozilla, Netscape,
or Opera browser (i.e., /usr/lib/mozilla): /usr/bin/firefox

WARNING: /usr/bin/firefox is not a directory.

Here are the tricks to fix it:

• it seems the Adobe installer wants the actual numbered version of the firefox directory. "whereis firefox" didn't help me in this respect (as suggested on help forums). I ended up using /usr/lib/firefox-3.0.1 Yours might be slightly different. Why Adobe couldn't have indicated this in the installer... I don't know. Twits.
  
• when testing out whether flash works on something like YouTube, make sure you don't have something like the "NoScript" add-on preventing anything you may need. (D'oh!) I had to allow both youtube.com and ytimg.com in NoScript.
  

... that brings up the question whether flash was actually working all along and my NoScript was thwarting all my efforts. Oh, probably.