My incoming mails have a subject line “[SPAM] KYOcount system report” and are no longer collected by the manager. Where is the word [SPAM] coming from and how can I remove it from the subject line, to be able to collect emails by the manager again?

The answer to this question falls apart in two items. First the word [SPAM] is added by the mail server when the incoming mail passes a (software) spam filter, there is nothing you can do except talking to the administrator and ask him to change the rules on the server. Second you should update to the latest (above 2200) build of KYOcount to overcome this security issue at the manager site.