When I try to play any game on Facebook it doesn’t work. There is just a large vertical line where the game should be.
one of the main reasons could be your slow internet connection...
try refreshing your page a few times ..or switching over to faster net services
Disable all adblock software.
Use a different browser such as Google Chrome.
If you are using any blocking software such as "Adblock" or "Flashblock" make sure its allowing that page.
You should clear your browsing data too.
Most of the online games are flash based.So,you need to have Adobe flash player updated to latest version so as to ensure no hiccups on software front.If flash player is set to hardware acceleration mode then you need to also update the drivers of graphics card too.At last your browser must also be updated so as to take advantage of latest features offered by these games.