Hello, i have a home made cnc machine i useded with aspire since lot of time. now i get mastercam 2018 to try it. i have no experience with this software. i try to configure machine and post but i get an error when i try to update post fom mach3 web sit(MasterCam_MACH3B.pst). when i try to update i get this page:

selected post were not all valid. detected post previous to mastercamx version, already updated,read only, binned post or not mp style post file.

at this time i have a 3 axe cnc machine but I when to update to have a 5 axe.
can anybody can help me to understand how to configure mastercam for mach3?

Thanks