If you are getting a "File Not Found Error" while playing on Chrome, please try following solutions:
Solution 1.
1. To improve Performance, Please clear your Chrome's Cache
  • From the “Menu button in the upper-right corner of the Chrome window, choose “More Tools” > “Clear browsing data…“.
  • Select the period of time you wish to delete cached information using the “Clear the following items from” drop down menu. From there, you can choose “Cached images and files“.
  • Select the “Clear browsing data” button, and Chrome will clear your cache.
  • Now try Playing, if it still does not work move to next step.

2. Ensure your browser is up to date and that you are not blocking cookies
  • From the “Menu button in the upper-right corner of the Chrome window, choose “Settings” .
  • Click the "Show advanced settings" and go "Content Settings" and click it.
  • In the "Cookies" section of the dialog that appears, make sure "Allow sites to save and read cookie data" is enabled
Solution 2.
Try Playing in incognito mode
  • From the “Menu button in the upper-right corner of the Chrome window, choose" New Incognito Window"
  • Go to Facebook and start playing your game like you normally do.
Solution 3.
If you're still having problems, please try playing on another browser.