What is vierd now is 3.5 can't compile the model.
It says:
Failed to create BGL file, and:
OutputFile: _temp.MDL
Output file after modification: _temp.MDL
Creating output MDL file: _temp.MDL
CRASHTREE no granularity specified
CRASHTREE completed in 00:00:00.0136710
Usage: XToMDL.exe /KEEP /NOGUI /BATCH /NOCRASH /BMP2DDS /XMLSAMPLE /XANIM /DICT

ictFileName /OUT:OutfileName Filename.X
I have installed the following:
Microsoft Flight Simulator Software Development Kit (SDK)
To assure maximum compatibility with Microsoft’s Flight Simulator 2004 and FSX, FS Design Studio creates new aircraft and scenery using the tools provided by Microsoft in their Software Development Kits (SDKs).
For FSX, you'll find the SDKs on the FSX Deluxe DVD #1 in the SDK folder. There is also Service Pack 1 update to the FSX SDKs that you must download from Microsoft’s website as well. The FSX SDKs are not available for download and are only found on the FSX DVD #1. To download and install Service Pack 1 update, you will have to have the SDKs from the FSX DVD #1 previously installed from Microsoft’s website.on DVD #1 of your Microsoft Flight Simulator X package.
MSXML 4.0 - filename: msxml.msi (5MB)
MSXML v4 is a set of services required to operate XML-based programs. *.XML files are used by the compilers from the Microsoft Flight Simulator SDKs (MakeMDL, XtoMDL and BGLComp). You will have to have MSXML installed in order to create aircraft and scenery.
.NET Framework v2 - filename: NETCFSetupv2.msi (38.5 MB)
The .NET Framework is a software development platform developed by Microsoft that is required for the compilers from the Microsoft Flight Simulator SDKs (MakeMDL, XtoMDL and BGLComp) to operate.
DirectX 9.0c August Update or later - filename: directx_aug2007_redist.exe (60 MB)
Flight Simulator 2004 and Flight Simulator X both include DirectX 9.0c, however Microsoft has provided updates to DirectX since 9.0c.