pg_upgrade problem from 8.4 to 9.2 problems on OSX

I am trying to migrate from 8.4 to 9.2 on OSX 10.8 (Mountain Lion)

Both 8.4 and 9.2 have been installed with the installers for OSX from
EnterpriseDB

Both have been stopped.

As user postgres, I run the pg_upgrade command and get the error
'old and new pg_controldata alignments are invalid or do not match'

Is there anything I can do to correct this?

The 8.4 installation contains a lot of databases, so I would rather not do
pg_dump/pg_restore on every database unless necessary.

This is the actual command and output:

[/Volumes/DISK2/Postgres/9.2/data]$ /Library/PostgreSQL/9.2/bin/pg_upgrade
\
-b /Library/PostgreSQL8.4/bin \
-B /Library/PostgreSQL/9.2/bin \
-d /Library/PostgreSQL8.4/data \
-D /Volumes/DISK2/Postgres/9.2/data

Performing Consistency Checks
-----------------------------
Checking current, bin, and data directories ok
Checking cluster versions ok

old and new pg_controldata alignments are invalid or do not match
Failure, exiting