How to restore from backup to 8.4.3 server using 9.0 dump/restore

Server is

PostgreSQL 8.4.3 on i486-pc-linux-gnu, compiled by GCC gcc-4.3.real (Debian
4.3.2-1.1) 4.3.2, 32-bit

Backup is created using 9.0RC  pg_dump.exe file

Trying to restore from this backup to same server using 9.0RC pg_restore.exe
causes error

"..\pg_dump\pg_restore.exe" -h mysite.com  -U
eur1_owner -i --no-privileges --no-owner -d "eur1" "C:\mybackup.backup"

pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 929; 2612 16389 PROCEDURAL
LANGUAGE plpgsql postgres
pg_restore: [archiver (db)] could not execute query: ERROR:  syntax error at
or near "PROCEDURAL"
LINE 1: CREATE OR REPLACE PROCEDURAL LANGUAGE plpgsql;


How to restore from this backup to 8.4.3 server using 9.0 pg_restore ?

Andrus.