Ok, so I tested this in 4.13RC04 Modact 6.01 (with Bf-109 Ultimate mod working) and found two things:
1. The Bf-109L-1 has the problem that dirtbloxx mentions. Only lines in log pertaining to it are these:
Created a 1024x1024 RenderTexture with BPP(8, 8, 8, 8)
Depth = 24, stencil = 8
Loading vertex/fragment programs: *706801696*
*** Loading: [vpFogFar2Tex2D]
*** Loading: [vpFog2Tex2DBlend]
*** Loading: [vpFogFar4Tex2D]
*** Loading: [vpFogFar8Tex2D]
*** Loading: [vpFogNoTex]
*** Loading: [vpFog4Tex2D]
*** Loading: [vpFog4Tex2D_UV2]
*** Loading: [vp4Tex2D]
*** Loading: [vp6Tex2D]
*** Loading: [vpTexUVTex2D]
*** Loading: [vpWaterGrid_NV]
*** Loading: [vpWaterSunLight_NV]
*** Loading: [vpWaterSunLight_ATI]
*** Loading: [vpWaterSunLight_FP]
*** Loading: [vpTreeSprite]
*** Loading: [vpTreeTrunk]
*** Loading: [vpVAObjectsN]
*** Loading: [vpVAObjectsL0]
*** Loading: [vpSprites]
*** Loading: [vpSimpleGL]
*** Loading: [fpWaterSunLightFast]
*** Loading: [fpWaterSunLight]
*** Loading: [fpWaterSunLightBest]
*** Loading: [fpCoastBump]
*** Loading: [fpCoastFoam]
*** Loading: [fpCoastFoamFast]
*** Loading: [fpCoastFoamFarFogTex]
*** Loading: [fpCausticSimple]
*** Loading: [fpCaustic]
*** Loading: [fpSprites]
*** Loading: [fpObjectsL0]
*** Loading: [fpObjectsL0_2L]
*** Loading: [fpSimpleGL]
*** Loading: [fpNearLandFog]
*** Loading: [fpFarLandFog]
*** Loading: [fpRiverCoastAA]
*** Loading: [vpWaterDM_CPU]
*** Loading: [fpWaterDM_CPU]
*** Loading: [fpWaterDM_CPULo]
*** Loading: [fpWaterLFogDM]
*** Loading: [fpIceWater]
*** Loading: [fpNearNoBlend]
*** Loading: [fpNearNoBlendNoise]
*** Loading: [fpNearBlend]
*** Loading: [fpNearBlendNoise]
*** Loading: [fpFarBlend]
*** Loading: [fpForestPlane]
*** Loading: [fpForestPlaneNoise]
*** Loading: [fpForestPlaneEdges]
*** Loading: [fpForestPlaneEdgesNoise]
Load bridges
Load static objects
##### House without collision (3do/Buildings/Furniture/10x1_5_White/mono.sim)
##### House without collision (3do/Buildings/Port/BaseSmallSegment/live.sim)
FM called 'FlightModels/BF109L1.fmd:BF109L_FM' is being loaded from File: 'bf109l_fm'
FM called 'FlightModels/DB606:BF109L_FM.emd' is being loaded from File: 'bf109l_fm'
Flight Model File FlightModels/BF109L1.fmd:BF109L_FM contains no Mach Drag Parameters.
FM called 'FlightModels/BF109L1.fmd:BF109L_FM' is being loaded from File: 'bf109l_fm'
ERROR file: File users/vogel/Icons not found
Mission: Quick/Smolensk/SmolenskBlueScramble01.mis is Playing
-------------------------------- MISSION FAILED ---------------------
warning: no files : music/crash
Cannot setup 3d algorithm.Settings will be reset to DEFAULT.
2. The Bf-109L-2 works perfectly. Even the default and MK-208 loads. However, I think this has more to do with the fact that I have a mod for the MK/MG-213 cannons working, which I assume the MK-208 in your mod is derived from, so that probably is the "fix" there.
This is a neat WIP, I'm looking forward to where this goes