Avisynth preview error:

[Selur]

ClearAutoloadDirs()
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\LoadDll.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\AddGrainC.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\dfttest.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\EEDI2.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\eedi3.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\FFT3DFilter.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\masktools2.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\mvtools2.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\TDeint.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\VerticalCleanerSSE2.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\RgTools.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\MedianBlur2.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\nnedi3.dll")
LoadPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\nnedi2.dll")
LoadCPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\yadif.dll")
LoadDLL("C:\Program Files\Hybrid\32bit\avisynthPlugins\libfftw3f-3.dll")
Import("C:\Program Files\Hybrid\32bit\avisynthPlugins\QTGMC.avsi")
Import("C:\Program Files\Hybrid\32bit\avisynthPlugins\SMDegrain.avsi")
Import("C:\Program Files\Hybrid\32bit\avisynthPlugins\Zs_RF_Shared.avsi")
LoadCPlugin("C:\PROGRA~1\Hybrid\32bit\AVISYN~1\ffms2.dll")
SetFilterMTMode("DEFAULT_MT_MODE", MT_MULTI_INSTANCE)
# loading source: D:\Video\UNNAMED DISC\2006 - Udo Music Festival Fuji Speedway.mkv
#  input color sampling YV12@8, matrix:Rec.709, scantyp: top field first
#  input luminance scale tv
Source = FFVideoSource("D:\Video\UNNAMED DISC\2006 - Udo Music Festival Fuji Speedway.mkv",cachefile="C:\Windows\Temp\mkv_a465d645c614698d0466fbe84c48ae4a_853323747_1_0.ffindex",fpsnum=30000,fpsden=1001,colorspace="YV12")
# cutting from 207 with 112661 frames - WARNING: This might cause synch issues
Source = Source.Trim(207, 112454)
# current resolution: 720x480
# deinterlacing
SourceFiltered = Source
Source = Source.AssumeTFF()
Source = Source.QTGMC(Preset="Slow", InputType=0, TR2=1, Sharpness=1.0, SourceMatch=0, Lossless=2, ediThreads=2, FPSDivisor=2, PrevGlobals="Reuse")# added PrevGlobals="Reuse" to handle multiple QTGMC instances
SourceFiltered = SourceFiltered.AssumeTFF()
SourceFiltered = SourceFiltered.QTGMC(Preset="Slow", InputType=0, TR2=1, Sharpness=1.0, SourceMatch=0, Lossless=2, ediThreads=2, FPSDivisor=2, PrevGlobals="Reuse")# added PrevGlobals="Reuse" to handle multiple QTGMC instances
# cropping
Source = Source.Crop(2,58,-6,-58)
SourceFiltered = SourceFiltered.Crop(2,58,-6,-58)# 712x364
# filtering
# scaling to 712x412
Source = Source.BicubicResize(712,412)
SourceFiltered = SourceFiltered.nnedi3_rpow2(rfactor=2,cshift="GaussResize",fwidth=712,fheight=412)
Source = Source.ColorYUV(analyze=true)
SourceFiltered = SourceFiltered.ColorYUV(analyze=true)
# stacking horizontal for filter preview
# adjust color to RGB32
SourceFiltered = SourceFiltered.ConvertToRGB32(matrix="Rec601")
# adjust color to RGB32
Source = Source.ConvertToRGB32(matrix="Rec601")
StackHorizontal(Source, SourceFiltered)
PreFetch(6)
return last

Script looks fine to me.
Similar script:

ClearAutoloadDirs()
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\LoadDll.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\DGDecodeNV.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\AddGrainC.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\dfttest.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\EEDI2.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\eedi3.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\FFT3DFilter.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\masktools2.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\mvtools2.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\TDeint.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\VerticalCleanerSSE2.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\RgTools.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\MedianBlur2.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\nnedi3.dll")
LoadPlugin("I:\Hybrid\32bit\AVISYN~1\nnedi2.dll")
LoadCPlugin("I:\Hybrid\32bit\AVISYN~1\yadif.dll")
LoadDLL("I:\Hybrid\32bit\avisynthPlugins\libfftw3f-3.dll")
Import("I:\Hybrid\32bit\avisynthPlugins\QTGMC.avsi")
Import("I:\Hybrid\32bit\avisynthPlugins\SMDegrain.avsi")
Import("I:\Hybrid\32bit\avisynthPlugins\Zs_RF_Shared.avsi")
SetFilterMTMode("DEFAULT_MT_MODE", MT_MULTI_INSTANCE)
# loading source: F:\TestClips&Co\files\interlaceAndTelecineSamples\interlaced\burosch1.mpg
#  input color sampling YV12@8, matrix:Rec.709, scantyp: bottom field first
#  input luminance scale tv
DGSource(dgi="E:\Temp\mpg_9f66a10dd7c34fcf28a5513f1347c0b5_853323747.dgi",fieldop=2)
# current resolution: 720x576
# deinterlacing
AssumeBFF()
QTGMC(Preset="Slow", InputType=0, TR2=1, Sharpness=1.0, SourceMatch=0, Lossless=2, ediThreads=2)
SelectEven()
# cropping
Crop(2,58,-6,-58)# 712x460
# filtering
# scaling to 712x412
# using lanczos resize instead of nnedi3 since needi3 can only be used for upscaling
LanczosResize(712,412)
PreFetch(8)
return last

works fine here without a problem.

Might be a problem with the source filter having problems with the source.
-> I would suggest trying a different source filter,

Cu Selur