lead error versus backlash compensation

First off...
Thanks to all who responded to my question about way
covers. I'll pipe in with a comment or two as well.
Neoprene is strange stuff; it comes in all sorts of
forms... Everything from a permeable "sponge" type that
is used on wet-suits, or a totally water tight material
for dry-suits, and finally to.... you guessed it.... way
covers. In fact, MSC sells a set of for BPort type
mills that are specifically listed as being neoprene.
Anyhow, neoprene does work well and is more than
suitable for light milling applications; Jon Elson
touched on this. It might not be suitable for 15HP Haas
power mills, but for the mills that 99% of us are using,
neoprene works great. McMaster-Carr, by the way, seems
to have a fairly nice selection. Again, thanks to all.

Now for my next question, and one I'm almost embarrassed
to ask (because I should know the answer). What is the
exact difference between lead error and backlash?
Backlash is pretty easy. It is the amount of rotation
your screw turns (translated to distance, of course)
without moving the table when reversing direction. My
understanding of lead error is that it is the amount of
error between the commanded position and the actual
position that a control will tolerate before tripping a
fault.

Is that accurate? My Hurco control that I'm slowly
bringing alive (great project, by the way... I've had a
ball with it and learned a ton about archaic controls)
has the ability to set DIP switches for both. I can
measure the backlash easily enough, but the lead error
is where I'm questioning how to proceed. If my
summation is correct, I assume that you just keep
increasing the lead error until the machine no longer
trips out with an axis error (assuming such a situation
really does not exist). Is my thought process correct?

Thanks in advance,
Alan