Dear Hannes,
thank you for your question.
As you are trying to install the ADONIS Business Process Management Toolkit, I would kindly ask you to get in touch with the ADONIS Community Edition Support Team/Helpdesk available online at
http://www.adonis-community.com/.
In the support section of their website (
http://en.adonis-community.com/welcome/support/) you can find documented support cases and also create a new ticket for your installation issue.