Ray - sorry, you got caught in a bit of a catch-22 situation -
MSM requires 3.43.22 or later - which the readme file calls out before you start installation of the software.
But, since you didn't have the readme file - catch-22.
I can't make MSM detect the 3.42.xx series of mach as the call to get mach's version info does not exist in 3.42.xx...
If you have run the MSM installer, the docs are all in c:\mach3\documentation\MachStdMill\
Please do look thru the readme file before going to much further so that you will have read the first time install instructions.
Dave