Hi,
Are you running the demo on WinXP or Win7? Did you follow the instructions in "Freescale USB device stack user guide" to install the USB driver? I found some problem when manually install USB driver for printer class demo on Win7.
Only after you have installed the driver, will the device listed in "Printer and Fax" lists.
So when you print a document, did you choose the printing device associated with printer class demo?