crap usb-rs232 chip probably, what do you honestly expect for 5.11£?
of which say 1£ will go to royal mail and packing, 50p to ebay/paypal, leaving ~3.50 for a cd (with a probably cracked FTDI driver to work with the forged chip as a cable with genuine chip costs more) and then the actual components, a PCB and their assembly (not to forget shipping from China)?
also don't discount the laptop itself, try a different machine if you have one. you might get lucky and get it to work.
what kind of latency time do you get when you run it with vcds light?