URGENT: where to find info about the pg structure

Hi all,
I posted today message about pg globals directory corruption.

I am using pg 7.3 on linux with reiserfs.

My problem is where to find more info about the pg structure.

To this moment I created one new db with the same structure as my
original.
I was able to finf the filename of one from my tables into the new db.
Also I have this file from the corrupted system.

I stoped the db and make copy over the new file.

After bd start I am not able to any data in pg.
Pg report:
LOG:  database system is shut down
LOG:  database system was shut down at 2003-05-29 17:46:10 EEST
LOG:  checkpoint record is at 25/2B043768
LOG:  redo record is at 25/2B043768; undo record is at 0/0; shutdown
TRUE
LOG:  next transaction id: 4607583; next oid: 52623925
LOG:  database system is ready
PANIC:  read of clog file 4, offset 196608 failed: Success
LOG:  statement: vacuum full analyze verbose a_nomen;
LOG:  server process (pid 1455) was terminated by signal 6
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing shared memory and
semaphores
LOG:  database system was interrupted at 2003-05-29 17:49:18 EEST
LOG:  checkpoint record is at 25/2B043768
LOG:  redo record is at 25/2B043768; undo record is at 0/0; shutdown
TRUE
LOG:  next transaction id: 4607583; next oid: 52623925
LOG:  database system was not properly shut down; automatic recovery in
progress
FATAL:  The database system is starting up
LOG:  ReadRecord: record with zero length at 25/2B0437A8
LOG:  redo is not required
LOG:  database system is ready
LOG:  smart shutdown request
LOG:  shutting down
LOG:  database system is shut down
LOG:  database system was shut down at 2003-05-29 17:49:58 EEST
LOG:  checkpoint record is at 25/2B0437E8
LOG:  redo record is at 25/2B0437E8; undo record is at 0/0; shutdown
TRUE
LOG:  next transaction id: 4607583; next oid: 52623925
LOG:  database system is ready


Is it possible to replace the files with my "old" files and if yes how?
Any idea will help.
regards,
ivan.