Welcome to the fun world of Avisynth.
The official 32-bit had most plugins, works well, but is slower.
The MT 32-bit build is faster, with MT scripting, but some plugins balk, and can fail to work properly or at all. I've quit using MT because I'd too often get glitched frames.
The x64 bit + is faster yet, but has less filters. I mostly use this for QTGMC and KNLmeansCL, but I'm trying to expand.
I do not use 32-bit + version, inferior to official from what I've experienced and read.
Avisynth is a constantly changing amoeba of a freeware, and can be hard to follow at times. But worth it.
I've learned quite a bit from selur's Hybrid, the most recent releases. He had both Avisynth and Vapoursyth embedded, and you can learn from the scripts created by it. Quite useful.
AvsPmod has both x86/32-bit and x64 versions. Use the same bit level for the Avisynth script.
Same for
VirtualDub. Use VirtualDub2 x64 for x64 avs scripts, and
VirtualDub official/regular for 32.
Got all that?