Hello cinema4d,
Apparently you're installing ProcessMaker in Apache's public html directory.
You can install ProcessMaker in any directory as long as ProcessMaker's main directory is "processmaker" but it is not recommended to install in on Apache's public html directory for security reasons.
Also you can't install ProcessMaker to be accessed through a subdirectory in a domain, like http://<mydomain.com>/processmaker. ProcessMaker has to be always installed in the main domain's directory, as in http://<mydomain.com.
If you need/have some other web application or site installed in the main domain's directory, then you can have ProcessMaker run from a port other than 80, as in http://<mydomain.com>:8080. That way you can have your main domain hosting something else and ProcessMaker hosted in port 8080.
ProcessMaker uses a redirector in order to get Apache to use ProcessMaker's main public html directory which is located at: ...\processmaker\workflow\public_html\ and this directory is defined as ProcessMaker's main public directory in the "pmos.conf" file located at: ...\processmaker\etc\.
Since you're installing on XAMP in Windows, you have to use ProcessMaker's source code file (.tar.gz) to do the install, not the .exe Windows installer which already comes with customized instances of Apache, PHP and MySQL for ProcessMaker and is overall easier to install since everything is pre-configured for ProcessMaker.
In order to install from the source code file, you have to carefully follow our Generic Installation Directions from the Wiki here:
http://wiki.processmaker.com/index.php/ ... stallation.
And for clear directions on installing ProcessMaker in a Windows server using the automated windows installer file (.exe), please read our Wiki:
http://wiki.processmaker.com/index.php/ ... stallation.
Hope that helps you,
And thank you for your interest in ProcessMaker.