This is typically because your USB header is plugged in upside down. Try flipping it and AS should find your aquero. You may even be able to do this while the computer is on (though don't blame me if you short something).

Interesting. I'm using Windows 7 x64 as well.
Unplug the cable, start Aquasuite, then plug the cable back in. Aquasuite should pick up the controller automagically.

If you unplug the Pro from the MB header does it still show an unknow device. Just checking in case it is not picking up the Pro at all.

Once you determine this, and it is showing the Pro as an unknown device. Unplug your mouse (if a USB mouse and reboot the system, then try to update the driver for the unknown device (I know it may be a little tricky without a mouse and you do nto have a spare one) run AquaSuite and see if that helps. Some users have reported that their USB mice interfere with the connection to the Aquaero but this is normally for firmware updates, worth a try though.

It is clearly an issue that Windows is not picking up the Pro properly or not able to install the driver correctly. If the above fail do you have a spare USB header cable you can try, also double check that it is wired correctly. I am assuming you have full admin rights to Windows, just in case.

Sorry, just re-read your post, ignore the first part of my post.

Quoted from "IceByte"

I have no clue if i can manually install the needed usb driver, if that's possible, i might be able to get the thing to work

Have you tried updating the driver in "Device Manager" under "Control Panel"?
When you open device manager, you should see an icon with a question mark attached to it for any unknown device on your system. If you right-click on the icon a menu will pop up with the option to "Update Driver Software" or alternatively you can go into "Properties" and then under the "Driver" Tab is a button to "Update Driver".

There is no special driver required at all.

All our USB devices are programmed as HI-Devices like you may know it from keyboards or mice. Every operating system can detect these devices and the software just communicates with the device directly.

Make sure that you are using the aquaero 2012 because "scanning for devices" sound a bit like you are using aquasuite 4.72 which is not compatible to the aquaero 5.

If it does not work on your PC, have you tried it on another to check if maybe your PC is the problem?