you have to e-file the Federal in order to be able to e-file any state. make sure when you get to the dialog box for transmitting your return you select e-file for Illinois. when you transmit your return both federal and state will be e-filed. if you already e-filed your federal you can e-file the state but you must select to mail in the federal return. then efile state and finally, you'll be able to e-file Illinois for which there is a fee.
