Mastav , currently the firmware extraction tool only supports upto v9.0.43. No one is able to extract their working v9.0.50 firmware for you to try on your player, so your version has very limited firmwares available.
There are a few v9.0.50 firmwares in here
http://www.mympxplayer.org/actions-9...mare-dc37.html
Also try searching the CD that came with your player, sometimes the firmware is inside. It should be in .bin or .fw extension.
You can try contacting your seller too, see if they have the firmware to send to you.
However, if they do not work, try the other v9.0.43 and v9.0.48 in the downloads section too. Just give them a try as you can't do anything until the firmware extraction tool can support your version.