Xtrabackup Restore Error!!

Hi All,

I am running Server version: 5.5.30-30.1-log Percona Server (GPL), Release rel30.1, Revision 465, also I am taking backup from innobackupex-1.5.1 backup part is working fine I am taking diff backup every hour.

When I tried to restore DB from the backup I got below error

 Version string '' contains invalid data; ignoring: '' at /usr/bin/innobackupex-1.5.1 line 1719.

Unknown option: incremental-dir

What this error is? 

I am trying to restore backup to percona Mysql 5.0.

Do you have run the restore command with an “–incremental-dir” option?

Read [url]Percona XtraBackup on restoring incremental backups.

yes I am using this option “–incremental-dir”