Redmine fetching e-mails: task not ending

Hello all,

i am successfully fetching emails from our IMAP-server using the following batch-file under Windows XP:

rake redmine:email:receive_imap host=myhost username=myuser password=mypassword RAILS_ENV=production project=Eingang tracker=Eingang priority=Normal unknown_user=create --trace

After fetching the emails the process 'ruby.exe' is still running with about 25% of CPU-usage, the DOS-box does not close, CTRL-C and CTRL-Z are not working.

Is there a way to stop the process after fetching emails, because i want to fetch emails every x minutes by using a cron-job...

Thanks in advance Holger