Problems with postgres online backup - restore

I started an online backup of postgres, tar'd my data folder, copy to usb
drive in production
and restored it into my RC environment. Have I missed something important?

When starting the database I receive many errors that look like the backup
was corrupted.

2009-06-23 08:29:15 EDT:@:7614ERROR: xlog flush request 10D/590D6578 is not
satisfied --- flushed only to 10D/510C4FB8

2009-06-23 08:29:15 EDT:@:7614CONTEXT: writing block 2 of relation
16403/16884/2696

2009-06-23 08:29:16 EDT:@:7614ERROR: xlog flush request 10D/590D6578 is not
satisfied --- flushed only to 10D/510C4FB8

2009-06-23 08:29:16 EDT:@:7614CONTEXT: writing block 2 of relation
16403/16884/2696

2009-06-23 08:29:16 EDT:@:7614WARNING: could not write block 2 of
16403/16884/2696

pgdb001=> select criteria_rank from client001.t1020screen where
criteria_rank like '%TR009%';

ERROR: missing chunk number 0 for toast value 738680

Version

[postgres(at)pgprd01 data]$ cat PG_VERSION

8.3

Online Backup

psql

checkpoint;

SELECT pg_switch_xlog();

SELECT pg_start_backup('postres_full_backup_June222009');

tar -czvf pgprd01_June22_2009_production.dmp.tar.gz data/

SELECT pg_stop_backup();

Restore

tar -xzvf pgprd01_June22_2009_production.dmp.tar.gz