I had the same issues trying to let amBX work on Windows 7 Ultimate.
I first installed all the drivers while the system was connected to my computer.
After i read on this forum and the wiki pages i shouldnt install with ambx connected.
Although not yet officially supported, quite some users have had success installing the Philips amBX kit drivers on Windows 7 32 and 64-bit. Try this at your own risk.
Do not connect the hardware yet.
Install the amBX web installer as normal.
Get all the latest updates as described above.
Open the Device Manager and click on your computer to activate it, then from the "Action" menu choose "Add legacy hardware".
Click to choose the hardware from the list, then Have Disk, and navigate to "C:\Program Files (x86)\amBX\Hardware" and choose either of the two .inf entries.
Connect the amBX hardware. It will fail to install. To install the device driver, click "Update driver" at the unknown device and again Have Disk (still "C:\Program Files (x86)\amBX\Hardware").
So i uninstalled everything and reinstalled without the system connected to pc.
I updated like 3 times untill there were really no further updates.
In Device Manager i referred to the ini files but that didnt work.
Later i deleted the unknown devices (ambx) in device manager and let
windows 7 search for new devices.. but still no use.
Than i found 2 icons in device manager with a ! in triangle mark!
I deleted those and let windows seven search again for new devices.
He found amBX and it all works now!
everything no errors or disfunctions found!
Right now im at work, but if moderators appreciate it i can post amBX diag when im back home?