The error you are seeing is a known issue with 12.6.8 CR1. To resolve this please try the steps below.
1. Backup and remove dxserver executable within dxserver/bin directory
2. Extract the installer package (Data1.cab) and remove the dxserver executable from that directory
3. Place the new dxserver executable in the dxserver/bin directory and properly name the file
4. Run the installer, right after the installer passes the version check. Place the original dxserver executable back.
5. Complete install.