Error when trying to recover from filesystem backup

Hi, folks!

Due to a hardware (hard disk) problem, we've tried to restore a
postgresql filesystem backup (taken from what was left on the drive)
to a fresh Postgresql install (as stated in
http://www.postgresql.org/docs/8.1/interactive/backup-file.html),
checking the appropiate ownership, privileges, etc. But when trying to
start Postgresql with the recovered location, we get the following
error:

" * Error: The server must be started under the locale : which does
not exist any more."

Note that the message doesn't say which locale is (allegedly)
missing!!! Both the crashed and the recovery machines have exactly
the same locales, Postgresql version, etc (Debian Etch standard with
postgresql-8.1 from main repositories), which makes the message a
little confusing. Google didn't help much, either (I've found
http://www.pg-forum.de/konfiguration/888-umzug-des-ordners-pgdata-auf-anderen-server.html
but can't really understand german).

Any hints to where should we look will be greatly appreciated!