Importing SQL file into PostgreSQL database

I work for a small college, where the library uses Evergreen to manage it's collection. The database is PostgreSQL driven. The server that Evergreen was running on crashed. The old server was running PostgreSQL 8.3. I've installed an updated version of Evergreen, including PostgreSQL 8.4.8. I have a backup of the database in a SQL file. When I try to import the file into the new database I get the following output:

postgres(at)server:~$ psql database < olddb.sql
SET
SET
SET
SET
SET
SET
setval
--------
23405
(1 row)

ERROR: function xml_is_well_formed(text) does not exist
LINE 1: SELECT xml_is_well_formed( $1 )

HINT: No function matches the given name and argument types. You might need to
add explicit type casts
QUERY: SELECT xml_is_well_formed( $1 )
CONTEXT: PL/pgSQL function "check_marcxml_well_formed" line 3 at IF
COPY record_entry, line 1: "-1 1 1 1 -1 2009-06-29 18:54
:59.184263+00 2009-06-29 15:54:59.184263+00 f f AUTOGEN-

1 FOO"

I saw that XML Functions need PostgreSQL to be configured with libxml at install. Is there a way around that? Can I install XML Functions into my server after the fact?

Thanks for any and all help!

Elliot Voris