Hi, welcome to the forums,
As the error says "No player found". Did you read the README file that comes with the plugin ? and configured the plugin correctly?
If you did and that's why it seems to try to execute /Users/gili/Downloads/Players/Flash Player.app, then you should know that the .app on Mac OSX is not a file, it's a directory and Mac makes it look like a file.. the real executable is hidden in "/Users/gili/Downloads/Players/Flash Player.app/Contents/MacOSX/<some filename>" you could also try adding "open" in front of line, like this :
open /Users/gili/Downloads/Players/Flash Player.app
as your player command.
Try that and see how it works.