Requested unknown parameter '[object Object]'

ivasya

When I tried to paginate my DataTable, or sort by field "category" I see "...Requested unknown parameter '[object Object]'"
So, here is my simple code:
http://live.datatables.net/zefalov/1/edit?html,js,output
I just want my DataTable in "category" column use not the <img> tag (which is content of <td>) for calculates, but use my special value in data-stars="some value".
I tried to use data-sort and data-order attrs, but it doesn't help.
I think this chapter can help me: http://datatables.net/reference/option/columns.render but... i don't understand yet, what I must to do.
Help me, please.
P.S. guys, sorry for my eanglish.