Cannot upgrade OFTP2 v35 to v36

Hello,

I'm trying to upgrade our current OFTP2 build 35 version to OFTP2 v39.

I'm following the instructions that are available in the readme file:

"*Create a backup of your installation
*Delete the existing jlib directories content
*Unpack the zip to the installation or execute the installer (windows). Do not overwrite the files that
contain your personal data like certificates.p12, certificates_ssl.p12 and the notification templates
*Start the OFTP2 server - it will start an update routine for the underlaying database structure - it's done. If additional
steps are required for the update process the system will inform you.
If the update fails please contact us.
*Whenever something unexpected occurs during this update procedure just recover the directory using your backup -
this will bring the server back to exact the old state"

When i launch the newly upgraded server by executing the executable 'OFTP2.exe' nothing happens.

Server OS: Windows server 2008 r2 standard.
Java version 1.8

Thanks in advance for the help.

Kind regards, Jonathan.