+1. Cable was going to be my first suggestion (yeah yeah!).
If the computer reported that too much current was being drawn and that the port was deactivated for safety, that means your cable has a short between pins 1+4 - 5v and ground.
Throw it in the bin.
Tascam tell you to use
their cable because they assume you're an idiot and you're going to force a scart lead in there or something.
The cable for the us1800 is generic. You'll find them at any electronics place...or probably in the back of your man drawer.
If you've had the same issue with two cables then I'd say that either the two cables are bad, or the computer/us1800 port is intermittently bad, allowing a short.
Do you have, and know how to work, a multimeter?
Try a different port on the computer to rule that end out.
You may need to restart every time you get a warning. I'm not sure how long your computer will deactivate the port power supply for each time.....Probably until reboot.