I am using AVISynth 2.5.7 rc1
http://www.free-codecs.com/AviSynth_download.htm

and FFDShow Tryout-248 clsid icl91 compile
http://prdownloads.sourceforge.net/..._clsid_icl9.exe

No error for the following AVS script:
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loadcplugin("C:\Apps\AviSynth257rc1\plugins\ffavisynth.dll")

green=Blankclip(pixel_type="yuy2",color=$800000,length=100,width=640,height=240,fps=15,audio_rate=8000).killaudio()
violet=Blankclip(pixel_type="yuy2",color=$80FFFF,length=100,width=640,height=240,fps=15,audio_rate=8000).killaudio()
interleave(green,violet)
assumefieldbased()
weave()
converttoyv12(interlaced=true)

ffdshow(preset="5-tap-lowpass")
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