Share the full stack trace error ( openkm.log ) here.
For playing with OpenKM I suggest using our development environment what comes as a virtual machine, take a look at download section https://www.openkm.com/en/download.html ( we have a video what explains how to install it )
For playing with OpenKM I suggest using our development environment what comes as a virtual machine, take a look at download section https://www.openkm.com/en/download.html ( we have a video what explains how to install it )