It looks like some function was not transferred correctly when you updated the database.
PG 4.6.1 and up was compatible with PG 7.3
The bittoint4 function used to be included in PG 7.2, but in 7.3 it had to be created for OpenACS. Its likely the upgrade script did not handle the fact that in 7.2 bittoint4 was a native function.
The fix is to execute the following command
psql -f packages/acs-kernel/sql/postgresql/postgesql.sql DBNAME
where dbname is the postgresql database name. Execute that from the openacs install root directory or modify the path to point to the postgresql.sql under acs-kernel.
