PMDG 737/747 and FsP

[Nasder]

SWAFO wrote:

Hmmm... Usually, you'll get the "Invalid NAV" message when you've got a VOR or LOC only frequency tuned and you attempt to activate
the approach mode of the autopilot.

That might be the issue, I never checked that it was the ILS frequency... It could have been the VOR... I kind of like took for granted it would give
me the ILS frequency as the PMDG 744 FMC does...