You need to put the ROM you copy from your calculator to your desktop in the same directory as VTI on the pocket pc (Program Files\VTI TICalc Emulator I think, I've uninstalled from mine til I get more RAM)
FWIW, TI puts the 89 ROM image up for free download on its website,
http://education.ti.com/us/product/apps/89/89os.html