combobox don't work because: "Uncaught TypeError: Cannot read property 'length' of undefined"

I've in the page several comboboxes. When I invoke an unique selector

("$('select').combobox()"), console return me this error:

Uncaught TypeError: Cannot read property 'length' of undefined

at line 432 of ui.combobox.js.

exatly the line is:

" if(!options.data.length) {

options.data = computedData;

}

"

thank you for the best work.