"A USB device is currently drawing too much power"

Question

I know it's a long post, but I just want to describe everything I've tried to do to solve the problem, so we can cut right to the chase
Yesterday I got this message when I plugged in my external harddrive (which is working properly btw): "A USB device is currently drawing too much power. The port it is attached to will be deactivated."
Today I haven't seen the message, but the USB port next to the Shift key on my MacBook isn't working very well.
Well, actually it works when I plug in my other external harddrive (which isn't usb-powered). So it seems that there's nothing wrong with the USB port itself. It just doesn't have the power it used to.
My USB-dongle from Cubase works fine. I tried another USB memory stick - it flashes very lightly and it won't mount. The other USB port - the one next to Caps Lock - works fine and it can even provide power enough for my MIDI keyboard and external soundcard.
I've tried resetting the PRAM/NVRAM and the SMC as people often suggest when this problem is described, but it doesn't help.
I've tried to do a full system check, and it says that there's no hardware errors.
I can imagine, that some would assume that the USB port is fried - but it can't be when the externally powered harddrive works fine when using the port.
I think is has to be some sort of software error. Is it possible that when OSX tells that "The port it is attached to will be deactivated" then the port needs to be reactivated somewhere?
I'm really looking forward for your answers

Answer 1

I don't know if this helps but...
I have five 24" iMacs in a education lab that keep telling me "USB Current Overload," even though only the Apple keyboard is attached. It seems they starting giving me the message the first time I turned them on. However, after a great talk with an Apple Tech person, we deduced that it must be a driver I installed on the five machines. We came to this conclusion because when I boot the machine from the OS CD, the problem doesn't happen. When I reboot from the hard drive, the message incessantly pops up, even with just the keyboard and mouse (that it came with) plugged in. On one machine in particular, the message pops up so many times that I can barely use the machine.
I have installed two external devices driver's on this machine, a Novation ReMote Compact SL driver and a TC Electronics 24 D firewire driver. I also have "frozen" these machines using DeepFreeze, which keeps students from installing things or chaning settings. My assumption is that one of these drivers is causing the bogus message. Since the computer works fine when booting up from the OS CD, this is the only thing that could be happening. Some other driver is causing the machine to think a USB device is drawing too much power. At least, I think this is what is happening. I'm still working on fixing this problem, but have not been successful yet with removing drivers.