Avisynth System Exception (Access violation MCTD) in Win7 64-bit

[Zergrinch]

I've recently moved to an I7 Windows 7 64-bit system (from Windows XP 32-bit). I've reinstalled AviSynth 2.5.8 (I didn't get the multithread version), and copied over my plugins directory from my XP system. Unfortunately, I'm now encountering some problems. Opening an AVS script in MeGUI gives the following error message:

Avisynth script error:
Evaluate: System exception - Access Violation

It references MCTemporalDenoise.v.1.4.20.avsi, line 700 as the culprit.

I examined Line 700 of the script (if I load MCTD 1.3, it references line 669) which says:

\ : i.FFT3Dgpu(sigma=sigma*0.8,sigma2=sigma*0.6,sigma3=sigma*0.4,sigma4=sigma*0.2,bw=bwbh,bh=bwbh,ow=owoh,oh=owoh,plane=chroma?4:0,bt=bt,precision=precision).gradfun2db(thr=1.0+sigma*0.05)

This appears to indicate a problem with FFT3D, so I downloaded a fresh copy from their website, placed it in System\sysWoW64\ and tried again.

Alas, same thing happens, so I'm currently at a loss on what to do.

I load plugins from a separate directory, after experiencing a particularly weird problem in the past caused by too many filters in the Avisynth\filters directory. For reference, my script is as follows:

LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\optional filters\SmoothAdjust-ICC-x86.dll")
LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\optional filters\gradfun2db.dll")
LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\optional filters\deblock.dll")
LoadPlugin("C:\Program Files (x86)\AviSynth 2.5\optional filters\TTempSmooth.dll")

Import("C:\Program Files (x86)\AviSynth 2.5\optional filters\GradFun2DBmod.v1.3.avsi")
Import("C:\Program Files (x86)\AviSynth 2.5\optional filters\MCTemporalDenoise.v1.4.20.avsi")
Import("C:\Program Files (x86)\AviSynth 2.5\optional filters\Deblock QED MT2.avsi")
Import("C:\Program Files (x86)\AviSynth 2.5\optional filters\LSFmod.v1.9.avsi")

AVISource("D:\Movies\!! RECODE\Dogs\2004-11-21 Christopher.avi", audio=false)
ConvertToYV12()

#denoise
SmoothLevels(Smode=2)
MCTemporalDenoise(settings="high", GPU=false)

#Adjust Colors manually
ColorYUV(off_v=-8, off_u=0, off_y=0)