virtualhost – Cannot access WebSVN webpage due to php error

On my private LAN, I have Synology DS918+ with operating system DSM 6.2.3-25426 Update 2. On this NAS I have installed SVN Server version 1.9.7-0119 (latest). Then I’ve installed WebSVN 2.5 (also latest) source into Synology’s WebStation as VirtualHost:
Synology's WebStation
with WebStation's settings:
WebStations' current settings
and virtual host is up and running. Now, when I try to acces WebSVN wepbage via, I get following error:

Unable to find “svnauthz” tool at location “/bin/svnauthz”

as you can see in following screenshot:
PHP Error
What did I my with installation?