As already pointed out, the problem is not prosody, but the version of the lua interpreter that is too old. Pick lua5.1 version 5.1.4-10 from unstable or wait 2 days (it will move to testing).
Cheers -- Enrico Tassi -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org