ispcp quota problem

[writetoanish1@hotmail.com]

Dear Sir/Madam,

I have installed ispCP 1.0.5 OMEGA in centos 5.4. When i tried to integrated the ispcp+quota, I am face the following error:


May 31 15:57:49 station185 dovecot: deliver(yunesh@testing.com): Fatal: Plugin sieve not found from directory /usr/lib/dovecot/lda
May 31 15:57:49 station185 postfix/pipe[2377]: 09E16AB5625: to=<yunesh@testing.com>, relay=dovecot, delay=15837, delays=15837/0.04/0/0.06, dsn=4.3.0, status=deferred (temporary failure)
May 31 15:57:49 station185 postfix/pipe[2373]: 53696AB5614: to=<yunesh@testing.com>, relay=dovecot, delay=80488, delays=80488/0.04/0/0.1, dsn=4.3.0, status=deferred (temporary failure)
May 31 15:57:49 station185 postfix/pipe[2370]: 0C842AB5635: to=<yunesh@testing.com>, relay=dovecot, delay=7166, delays=7166/0.01/0/0.05, dsn=4.3.0, status=deferred (temporary failure)

I have the follwing version of dovecot and postfix.
[root@station185 ~]# rpm -q dovecot
dovecot-1.2.17-2.0.cf.rhel5
[root@station185 ~]# rpm -q postfix
postfix-2.3.3-2.2.el5_6
[root@station185 ~]#

Please help me to solve this error.