When the Soldat Dedicated Server 2.5.4 download was posted on Soldat.pl (the full install only), the zip file was missing the logs/kills directory, and this would cause the server not to start.
If you downloaded just the patch, it should work fine.
If you downloaded soldatserver254.zip from Soldat.pl some time before this post and are having problems with your server, please re-download it.
I was helping two people with server-related problems on IRC and realized that this was the source of the problem
Please post here or join #soldat.servers if you have any questions