To be able to debug programs, you must provide ROM images for the calculators you wish to emulate.
They can be:

ti8x.rom - TI-83 Plus ROM [512KB]
ti83.rom - TI-83 ROM [256KB]
ti82.rom - TI-82 ROM [128KB]

You must prepare the ROMs beforehand (clean them up) by erasing any applications or programs on them.