Well, a rebuild sorted everything out. I don't know what caused the issue in the first place, but after installing

sudo -s
apt-get install libusb
cpan -i Inline::MakeMaker
cpan -i Device::USB
[download]

Everything went smoothly. Plus the rebuild gave me a chance to refine the rebuild script (gradually moving to shell script), fix a couple of problems I didn't know I had and even gave me a performance improvement.

Regards

Steve