Convolution3D and Reinterpolate411 are external plugins - they do not come with AviSynth.
You can either comment those lines out (just put a
# in front of them) or download the required plugins.
Reinterpolate411
http://mywebpages.comcast.net/trbarry/downloads.htm
Convolution3D
http://www.avisynth.org/warpenterprises/
You can put them into your \AviSynth 2.5\plugins directory and have them automatically loaded when required in a script or add a manual load-command (
LoadPlugin("c:\uvw\xyz.dll")) if they're located somewhere else.
For more information on how to use AviSynth refer to the
AviSynth website.