bootcamp wont install windows 7 - unable to create a new system partition (SOLVED)

[Nvidiaguy07]

Steps ive taken so far:

updated everything fully (10.7.2, etc)
Copied windows 7.iso to my mac desktop (msdn image, SHA1 checked)
ran bootcamp assistant
chose my iso, and then selected my 16gb patriot usb drive to copy the os to
windows support software on separate usb drve
chose to have partitions divided equally (60gb/60gb)
reboots into windows installer
gets to part where it asks "Where do you want to install windows?"

I follow the steps in the guide:
Disk 0 Partition 4 Bootcamp - click drive options - advanced
format and click ok
click next.... and then i get this error

"setup was unable to create a new system partition or locate an existing system partition. See the setup log files for more information."

Im stuck at this point, no matter what i try, i cant get past this point. Anyone else run into this problem? Id imagine anyone with an air who was installed windows 7 would have followed the exact same steps as myself right?

 

[Nvidiaguy07]

ok got it to work.

I guess because i had my os on one usb drive, and the software on the other plugged into the computer at the same time, it was screwing things up.

I unplugged the other and left only one drive in, rebooted and it worked. go figure.