I just did a fresh install on Windows XP SP2 and I'm having no issues.
Could you all kindly uninstall Soldat, delete the Soldat folder, remove any Soldat registry keys (hacked or otherwise) and then restart your computer.
Once that is done, reinstall Soldat to a new and different directory (as in C:\Soldat, or C:\Games\Soldat) and then start it up without making any setup changes (no mods, user preferences, etcetera).
Post your results here, please.