Could not find a valid simobject

Hi, Need some help from anyone that may know.

Been trying to create a livery project for the JustFlight Fokker 100 to get some repaints done. I set up the project in the same way that I have done for many other liveries which had worked fine in the past, but this time I’m running into an error.

“AssetBuilder | Could not find a valid simobject in ‘c:\users\tankb\onedrive\documents\myfsprojects\tank787f100livery\PackageSources\SimObjects\airplanes\tank787repaints_Tank787F100’. Does it have one of [aircraft.cfg / sim.cfg / container.cfg] and does it reference the correct model folder(s)?”

I have got an aircraft.cfg with all the correct model information in there, however I cannot build the package and run into this error everytime.
My only guess is that it has something to do with the aircraft being a non-modular aircraft, but I’m not sure.

Any help/guidance would be greatly appreciated.