You'd probably have better luck if you could somehow have your amination in the anim format, this is far better supported than AVIs.
I used to have a set of scripts and utilities that converted from a set of stills rendered on C4D on the amiga to an AVI file. Perhaps you could find some similar tools for that.
Sadly free screensavers (or blankers in Amiga parlence) seem to be rather few and far between.
