I can only really comment on the PC side of things as I'm still a 35mm chap !
The PC is simply protecting itself. USB ports are limited to 500mA each. The PC effectively has a USB hub inside as part of the USB controller so the message you received refers to that.
It would seem to me that the camera has a fault causing it to attempt to drawn more than it's allowance of 500mA.
Just as a sanity check it is worth checking that any other USB connected devices on the PC are working OK.
Apologies if that was a Grandmother & eggs response as I suspect it was !
Good Luck !