Saw the post on FFMPEG. Not being that technical, just wandering if a CMD file could be written to batch convert multiple AVI files (exisiting in a variety of subdirectories underneath a main directory) to FLV files to those same subdirectories? These subdirectories also contain many JPG files, which are already uploaded ZP.
I have searched the web for such a batch converter, but could not find any.

Best you refer to the FFMPEG forum if there is any. There are lots of tools for conversion out there.