See what Windows version(s) your device is compatible with and if not
supported in Vista, install/run them in relevant Windows version
compatibility mode.

FWIW, ran across this review while researching your unit:

8 of 10 people found the following review helpful:
2.0 out of 5 stars Installing drivers a nightmare, 16 Sep 2006
By     Dave345 - See all my reviews
This cable works, and I can upload and download routes to my GPS and see
my position on a map. The price is good, but if you can afford it spend
more money for better support.

I am giving this two stars because installing the drivers was a
nightmare. No CD was supplied. The drivers on the Manhattan web site use
a different chip set (Profilic), and there were about 4 to try. I then
got the vendor ID from USB identifier in the device manager, looked this
up (6547 - ArkMicro) and went to their web site. However I couldn't see
where to download the drivers from. I then signed up (expecting spam) to
driverguide.com and got the drivers from there. The drivers recognized
the hardware, but didn't work. I then had to allow the drivers to run
without them being signed, so goodness knows what this is doing to my
system integrity.