Hi I just had the same error, in my case I was using a sortname on a column I didn't use anymore.

I see you have your sortname defined as 'id', althought the column's name is '_id',

so maybe changing sortname: 'id' to sortname: '_id' could fix it.

It still would be useful if some kind of exception was throw if something like this occurs, could save a lot of time debugging things like this.