Recovering a broken database

Hello,

I'm having the almost exact problem described here:
http://archives.postgresql.org/pgsql-admin/2004-12/msg00110.php

That is, a 8.0 which started on a 7.4.2 repository. After noticing,
I switched back to 7.4.2, but now it gives this error and won't start:

FATAL: database files are incompatible with server
DETAIL: The database cluster was initialized with PG_CONTROL_VERSION 74, but
the server was compiled with PG_CONTROL_VERSION 72.
HINT: It looks like you need to initdb.

I read the pointer about using pg_resetxlog, but I obtain a seemingly
empty database (no tables). Here's the output from pg_resetxlog:

-------------------------
pg_resetxlog: pg_control exists but is broken or unknown version; ignoring it
Guessed pg_control values:

pg_control version number: 72
Catalog version number: 200310211
Current log file ID: 0
Next log file segment: 1
Latest checkpoint's StartUpID: 0
Latest checkpoint's NextXID: 514
Latest checkpoint's NextOID: 16384
Database block size: 8192
Blocks per segment of large relation: 131072
Maximum length of identifiers: 64
Maximum number of function arguments: 32
Date/time type storage: floating-point numbers
Maximum length of locale name: 128
LC_COLLATE: en_US.UTF-8
LC_CTYPE: en_US.UTF-8

If these values seem acceptable, use -f to force reset.
-------------------------

Then I use -f and it resets, but to no use.

I also tried recompiling 7.4.2 (I install it from source anyway) but
no use.

I did a backup of the repository before I attempted the reset.
Is there any other way I can try to recover the database?

--
Ciprian Popovici