You also need the appropriate drivers for your Hardware. There are Elvis-II drivers that you should be able to download from NI, but I'm surprised that it is not included with the other Elvis software. Do you have NI MAX installed? This is the NI's Measurement & Automation Explorer -- an interactive program that knows how to "talk" with most NI Hardware (and I'm assuming that includes the Elvis II). Do you have this icon on your desktop? (Ignore the violet background of my desktop) (there may also be a "pencil" in the upper right-hand corner, not sure who put that there ...).
If you don't have the Elvis drivers, you should be able to download them from here.
Bob Schor