for /f "delims=" %%a in (
'dir /b /a-d /tw /od "C:\FrapsFilmBuffer\*.avi"'
) do move "C:\FrapsFilmBuffer\%%a" "E:\Random\Fraps\Film" & goto fileMoved
:fileMoved
Getting the list of files in date order, you get the oldest file the first in the list. Move it and leave the loop