USB to serial, Prolific, problems

Hey

I just purchased a USB to serial converter cable, based on the Prolific PL-2303.

I tried installing it on my Vista machine, seemed ok, but the pc bluescreened a short while after I plugged it into my Arduino Severino. Now device manager says the device(converter cable) cannot start.

Tried on my XP machine, driver installs ok, but pin3 on the cable (Rx on arduino) is constantly 5v, and I can't upload any sketches - Rx led is just constantly lit.

Have anyone experienced this or do you have troubleshooting ideas?
Thanks

Ps. the board is working, and my other usb to serial cable (another brand) uploads sketches to it with no problems

I have seen nothing but problems with the Prolific chipset, on every platform. Which is unfortunate because most of the $10 adapters use them.

Fortunately I only paid £4 shipped, and I'm getting a replacement sent to me now, hopefully it'll work...