contrib/levenshtein() has a bug?

The levenshtein function from contrib/fuzzystrmatch.sql has a max arg
length of 255. OK, that's cool. But check this out:

mbrainz_db=> select max(length(name)) from public.track;
max
-----
255
(1 row)

mbrainz_db=> select levenshtein(name,'foo') from public.track;
ERROR: argument exceeds max length: 255

That seems odd. What's odder is:

mbrainz_db=> select levenshtein(substring(name for 100),'foo') from public.track;
ERROR: argument exceeds max length: 255

Any suggestions? I'm using the Fedora 5 rpms, so it looks like that puts
me at 8.1.4.