I am at my wit's ends here. I've tried duplicating the setup I have on one computer where Avisynth works properly on another where it does not.
I've tried duplicating every Avisynth file I can think of on the working computer but it's made no difference. All I can think of now is that I've overlooked something. Directories/files I've tried so far (That I can remember:)
\Program Files\Avisynth 2.5\plugins\
\Windows\System32\avisynth.dll (For good measure)
Installing same version of PS3 Media Server on both machines
So far the only progress I've made is that I needed to add "return clip" to the text under configuration. Now instead of not playing at all like it did before, I start with a black screen that is distorted whenever there is movement, and no subtitles. I think that is the ONLY noticeable change I've been able to make to the whole thing.
Old computer is Windows XP SP3, but new computer is Windows 7 64-bit.
(And it looks like the directions for installing Avisynth in English are missing on the FAQs page, I have looked for alternative installation methods.)