Strangest problem, and I still haven't figured out how to fix it. Found a workaround though...

On my main desktop I'm running Win7 32bit with all the latest updates installed. I tried flashing my N900 to give it a fresh start, and I figured I should flash both the fiasco and emmc. The strange problem was that the fiasco worked perfectly with just the flasher installed.

Flashing the emmc however failed every time, no matter what I tried. I disabled driver signing, I installed libusb and loaded custom drivers (the N900 showed in device manager), I even installed the latest Nokia Software Updater and tried updating the firmware through it. I also tried installing the fiasco followed by emmc (wrong order, but I just wanted to see if it would do something), I tried installing the emmc followed by the fiasco. NOTHING worked.

I did not try installing Windows XP mode on the desktop, or a linux bootable CD because I had another workaround. I booted my old windows XP 32bit computer, installed flasher, flashing emmc and fiasco worked perfectly.

The strangest thing is that about half a year ago I flashed my N900 on this exact same Windows 7 32Bit computer and it worked perfectly. My guess is that one of Microsoft's updates somehow messed up the USB system, bringing it inline with the Windows 7 64bit version.