pg_upgrade not detecting version properly

Hi all,

I'm trying to test using pg_upgrade to go from 9.1.6 to 9.2.1 on Ubuntu
server 10.04.  But when I run pg_upgrade, it tells me I can only run it
on 8.3 or later.

Old:
postgres=# SELECT version();
                                                    version

----------------------------------------------------------------------------------------------------------------
 PostgreSQL 9.1.6 on x86_64-unknown-linux-gnu, compiled by gcc-4.4.real
(Ubuntu 4.4.3-4ubuntu5.1) 4.4.3, 64-bit
(1 row)


New:
postgres=# SELECT version();
                                                    version

----------------------------------------------------------------------------------------------------------------
 PostgreSQL 9.2.1 on x86_64-unknown-linux-gnu, compiled by gcc-4.4.real
(Ubuntu 4.4.3-4ubuntu5.1) 4.4.3, 64-bit
(1 row)


Yet when I try to run pg_upgrade:

$ /usr/lib/postgresql/9.2/bin/pg_upgrade -b /usr/lib/postgresql/9.1/bin/
-d /postgresql/9.1/main -B /usr/lib/postgresql/9.2/bin/ -D
/postgresql/9.2/main -k -c -v
Running in verbose mode
Performing Consistency Checks
-----------------------------
Checking current, bin, and data directories                 ok
Checking cluster versions
This utility can only upgrade from PostgreSQL version 8.3 and later.
Failure, exiting

Any idea what could be going on here?

Thank you in advance for your help.

    - Chris