Postges 8.0.2 Online backup Errors!

Hi ,

      I got this error while doing my online backups on the new postgres
8.0.2. I follow the same procedure as mentioned in the docs and the way
i do in brief is

1) Put the database in backup mode with pg_start_backup
2) copy data cluster, I use tablespaces and my tables and indexes are in
different partition so i copy them also here using tar and gzip
3) And put the database back in normal mode with pg_stop_backup
4) copy archive log directory with tar and gzip.

    and today I go this error , i am not sure if  this is normal or is
this something to worry about ?  does anybody experienced anything like
this before ?

ERROR Durring Backup
--------------------------------------------------------------------------------
bash-2.05b$ ./backup.sh b
17/8E3DA9F0
tar: tabledata/165899758/165958430: file changed as we read it
tar: Error exit delayed from previous errors
17/8E8CB0A8
bash-2.05b$
----------------------------------------------------------------------------------

Thanks!
Pallav