When I run it I get a message saying "Could not find a FATX drive to open" I'm worried that thats happening because I have the new NXE update thing. Is that the reason or am I over-looking something?
Do you have vista. If so run the program as administrator. And make sure your hardrive is plugged into your pc. Try different usb ports too. The nxe update only banned some keyvaults it did nothing else for modding.
I'd double check the following :
1.) make sure it's all plugged in and hooked up correctly. like mojobojo said, try different usb ports. you should get a noise and a pop-up window in the task bar for a new drive when it connects.
2.) reinstall the software. it may have missed the drivers for the hard drives.
3.) do as mojbojo said if you're running Vista. run it as admin.
The NXE update has nothing to do with connecting your HDD to your PC. That error message has more to do with the connection or a rights to that drive issue.