error during PITR

Hello,

I doing PITR using following doc.
http://www.mkyong.com/database/postgresql-point-in-time-recovery-incremental-backup/

But when I am doing recovery till the specific time so I change parameter
in recover.conf file.
i.e. restore_command = 'cp /opt/PostgresPlus/archive/%f %p'
recovery_target_time = '2011-12-22 07:27:08'

when I restart ppas 9.0 server then I got following error: (this is in log
file)

LOG: database system was shut down at 2011-12-22 08:21:11 IST
LOG: starting point-in-time recovery to 2011-12-22 07:27:08+05:30
LOG: restored log file "000000010000000000000014" from archive
LOG: redo starts at 0/14000070
LOG: restored log file "000000010000000000000015" from archive
LOG: restored log file "000000010000000000000016" from archive
LOG: restored log file "000000010000000000000017" from archive
LOG: restored log file "000000010000000000000018" from archive
LOG: restored log file "000000010000000000000019" from archive
LOG: recovery stopping before commit of transaction 756, time 2011-12-22
07:29:08.152325+05:30
LOG: redo done at 0/2423F264
LOG: last completed transaction was at log time 2011-12-22
07:26:51.427245+05:30
FATAL: requested recovery stop point is before consistent recovery point
LOG: startup process (PID 5413) exited with exit code 1

Please let me know what is going wrong in that?
can any one please give me solution for this problem???

Regards,
Karuna Karpe.