What's the meaning of this error message “insertId: Error: INVALID_ACCESS_ERR: DOM Exception 15”?

I'm developing an app using jquery mobile, phonegap and openDatabase. When the app is executed, I can see in the console of Safari browser the SQLResultSet with this message:

insertId: Error: INVALID_ACCESS_ERR: DOM Exception 15. 

However, my app is working ok. But I don't understand why that message is shown.

Please, help me.