Cncpro/Gcode

Hi everyone!
I have some questions on CNCpro and G-codes. I worte a few of the
questions to yeager but its been about three days now with no
responce :( I thank him for providing GREAT programs but am a little
disappointed with the support considering e-mailing is the primary/
only way to contact him. For $200 (most expensive programs I have
ever bought-cncpro and ace converter) I was hoping for more help. I
have been trying to run his "help" file but cannot get it working. I
also don't find any newest exe files at his "download for newest exe
files :(" Anyone have the help file working or any newest exe files
that may make it eaiser for me to learn, that would be great!. I have
learned a lot by experimenting and trying to go over some of the
examples yeager gives.

Ok now for (most) of my questions, I thank all of you in advance for
your help.

1) What is F5-F8 I01-I04 for?
2) He talks about V (varibable) but I am not sure how to us this?
3) He talks about L (loop g-code) but I am unsure how to put this
into a line, can anyone please provide me with an example?
4) what is E-stop for? (emergency stop??)
5) How and why do you use subroutines?
6) why would you use tool "length" compensation?
7)how do you use machine offset coordinates?
8)do I generally want to keep <V> const. contour off or on?

Thank you again, I realize there are a lot of questions and any help
on any of them would be greatly appreciated!

take care
taus