PostgeSQL unable to restore database from previous version 7.2 to 7.3

I created the backup of the 7.2 database, removed the 7.2 database, and
installed the 7.3 database.
When I try to restore into the new 7.3 version, I'm getting this message:

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$ psql < backup
FATAL:  Database "hurstm2" does not exist in the system catalog.
psql: FATAL:  Database "hurstm2" does not exist in the system catalog.
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The 7.3 Postgres was created in the eact same location as the 7.2 cluster.
The user "hurstm2" issued the "initdb -D ..." command to created the
cluster.

So what would be causing this type of error message?

Thanks,
-Martin