Hi Dan,
You mean this one? (2011-05-21 PlugIn: SmoothStepper_v17d.zip)
It's not available for download anymore.
There are only these three available: 2011-10-30 PlugIn: SmoothStepper_v17efb.zip,
this: SmoothStepperUSBDriver2.08.02.zip
and this: SmoothStepperUSBDriver2.08.14.zip.
Anyways, it's going to be a while before I get my workshop operational and mill reinstalled and by the time I get round to it things may have changed so I'll keep my eye on things.
Many thanks,
Dave.