CLASSPNP.SYS error when trying to install W8 from USB

I have no DVD drive on my machine so Iam trying to install Windows 8 from an SD Card in a USB Reader (onto secondary HDD, my Primary is an SSD running Win7) which ive done successfully before, but now I get some error about CLASSPNP.SYS is corrupt and all i can do is reboot

anyone have any ideas?

I HAVE had problems installing from the card reader before but had got it working.. unfortunately I can install any other way, I have a USB HDD but its almost full and just dropping the install files into it wont work will it? as I had to specially format the SD Card with BOOTSECT.EXE etc to make it bootable or whatever

thanks in advance