You're running the game with the -dedicated parameter. If you're opening Soldat from a short-cut, right click and select Properties. Make sure the target says something like:
"C:\Soldat\Soldat.exe"
The exact text will vary depending on where you installed Soldat. But there can be no additional parameters such as -dedicated afterwards. If this fails, try running Soldat.exe directly from your Soldat folder.
