I'm using jqGrid 4.3.1 to create a treegrid with local data. I keep getting the following javascript error:

Uncaught TypeError: Cannot read property '0' of undefined

I can't figure out what is wrong with my jqGrid definition. I've looked at the wiki, the forums, and stackoverflow. It looks right to me, but I can't seem to figure this one out. Any help would be greatly appreciated. Here's my code: