Uncaught TypeError: Cannot read property 'substr' of undefined

[raghu64]

I added ga event on checkbox click and it's working fine. But its throwing me error on my subsequent clicks.

Uncaught TypeError: Cannot read property 'substr' of undefined(…) onEvent @ ga.js:54 defaultHandlerWrapper @ angular.js:3384 eventHandler @ angular.js:3372

and in my code i'm using the ga event as

and i'm using [email protected]

Can anyone help me in figuring out how to solve this issue.

Thanks