Bad USB port explanation?

[M. Warner Losh]

In message: <009e01c9ca01$356cca70$a0465f50$@com>
            "Engineering" <ee at athyriogames.com> writes:
: Only on one USB port is it going haywire. I can disconnect the camera while
: the app is running, move it to another port, and it pops up at 30fps. Move
: it back to the top left port, and it goes bad again.

I've seen three things cause this.  1: static damage.  2: improper
balancing of the inputs and 3: overloaded hub for other ports...

Warner