Hi!
There is nothing wrong with the plugin. You are setup it wrong.
First, ".css" is not a valid font format.
And the Font File must have the file extension.
The Font Face does not have file extension. It's just work like an ID to access the font inside game.
So, on Font File put: myFont.ttf
And on Font Face put: myFont
If still does not work, show me the error again and also a screenshot of your font folder.
sorry but not work... I don't know what happenned... same bug came out. 
