I can't to user 8x8 font

[chon27]

Hello,

I am having trouble about use 8x8 fonts. I did my png at http://arcade.photonstorm.com/ in the minimun size (8x8) and when I want to use it I receive an error:

 

Warning: Phaser.Cache.getImage: Invalid key: "yellowFont" 

Error: Uncaught TypeError: Cannot read property 'hasLoaded' of undefined 

 

I think I am loading correctly the png file because I have edited my old png file with a retrofont of 16x16. What is the problem?