Installation will not recognize my serial that was emailed it me, I tried MXinstall-helper and it did not find my programs? Need to get this working, as I uninstalled 15 before installing this one.
You can reinstall downloading your VEGAS Pro 15 e.g. from your MAGIX Account while waiting for this to get fixed. See e.g. here. Different numbered versions can co-exist on your computer
I assume you checked your "serial number for typos" and that you were "using the serial number matching to the program".