Problem with pg_upgrade from 9.0 to 9.1 under Ubuntu x64

Hi all,

I have a Linux/Ubuntu (10.04) x64 server on which I have installed PostgreSQL 9.0.4 by source compilation.
I have also installed PostgreSQL 9.1.0 with source compilation on the same server, and I try to migrate my data using pg_upgrade.

For PostgreSQL 9.0.4, the installation directories are :
- bindir : /opt/postgreSQL/9.0/bin/
- datadir : opt/postgreSQL/9.0/data/
- port : 5433 (specified in postgresql.conf)

For PostgreSQL 9.1.0, the installation directories are :
- bindir : /opt/postgreSQL/9.1/bin/
- datadir : opt/postgreSQL/9.1/data/
- port : 5433 (specified in postgresql.conf)

Both PostgreSQL server are shut down before migration.
I have compiled pg_upgrade 9.1 from the contrib source of PosgreSQL 9.1.0.

I use the following command :
/opt/postgreSQL/9.1/bin/pg_upgrade -v --old-datadir=/opt/postgreSQL/9.0/data/ --new-datadir=/opt/postgreSQL/9.1/data/ --old-bindir=/opt/postgreSQL/9.0/bin/ --new-bindir=/opt/postgreSQL/9.1/bin/ --old-port=5433 --new-port=5432 --user=postgres

And get the following message :

Running in verbose mode
Performing Consistency Checks
-----------------------------
Checking current, bin, and data directories ok
Checking cluster versions
This utility can only upgrade to PostgreSQL version 9.1.
Failure, exiting

Why do I get this error ?

Thanks in advance for your help,

Cedric Duprez