Redmine

Hi dear All,
I have some problem can you help me ?
I have installed Redmine Activiy Report plugin and do all configuration but cron job work with error

Mar 15 00:45:01 Razmik-PC CRON[10602]: (razmik) CMD (/bin/bash -l -c 'cd /usr/share/redmine && RAILS_ENV=production bundle exec rake activity_report:daily --silent
Mar 15 00:45:01 Razmik-PC CRON[10601]: (CRON) info (No MTA installed, discarding output)

i setup in redmine my local mail server settings(postfix ) and redmine recogize it and work fine i send test email from redmine settings and all is ok but cron job didnot send me any report (((((

Can anybody help me ?
Thanks in Advacne,
Razmik