Are you getting a Java security error when trying to run the FretboardMaster Applet? Java 7 Update 51 and later breaks any unsigned java applet. Unfortunately a certificate to sign the applet costs $100 per year!
So if you would still like to run the Fretboard Master applet, you will need to add this site to your java exception list. Instructions can be found here:
I aplogize for the inconvenience and not noticing this earlier. I can't afford $100 a year plus hosting costs, so this is best I can do for now. I am working on a mobile friendly version in my spare time, hopefully it will be done soon! Thank you for your patience and I hope you enjoy the game!