The explanation is simple:
In PG <= 7.2 names were truncated to 31 characters.
In PG 7.3 by default the truncation length is 63 characters.
A very simple way to upgrade would be to recompile PG 7.3 after changing the name length to the old 31 character value...
Someone is already working on gathering the functions that need to be redefined using CREATE OR REPLACE, so eventually we may have an upgrade script available.
