a) First, verify that Flash Player is installed and working on your system.
Check the Flash Player Version Detection page, here (the link is case-sensitive): http://adobe.ly/wRILS
b) If you see the box with version information, you have successfully installed Flash Player and will be able to view Flash content via the Android browser.
Open the Browser
Hit the Menu Button
Choose Settings > Enable Plug-Ins and make sure that it's set to Always On
If the settings above did not match, this probably fixed the problem.
Please visit the Flash Player Version Detection Page (http://adobe.ly/wRILS ) again.
If you see the version information now, you're done! Congratulations.
d) If not, it sounds like the installation did not work correctly.
First uninstall Flash Player by doing the following:
Go to Settings > Applications > Manage Applications > Adobe Flash Player
Hit Uninstall (or Uninstall Updates) and follow the prompts
Restart your phone. This will make sure that anything that might be keeping the Flash Player binary locked is no longer running.
Once the phone comes back up, open the Market and search for "Flash Player". Follow the installation prompts.
NOT an Adobe Employee but I've found my problem and it was with REAL PLAYER. if you have it, it will make your Adobe Flash Player unstable and not able to play videos or games in this case. I figured this out after watching a video on youtube then installing Real Player and the video i just watched (which I refreshed the page) and stopped working. Then I uninstall Real Player and and it's components and refreshed the video again and it worked. Note: this happens to Firefox.