Hello to all Space Siege fans.
Since mp saves stopped working in my WinXP after i installed an language interface pack, i suspected an localization/language settings problem.
My Windows 7 is Slovak by default, so i changed the Regional settings to Format to English, Location to USA and Unicode to USA.
That will change the date format and other regional settings to an English default.
However, the saves are not working just yet!
You have to make a .ssres file with the SSTankCreator tool and place it into your %gamedir%\Space Siege\resources.
You don't have to make a mod with changed files, one unchanged file will do. After that start SpaceSiege multilayer, change some skills, update some things and save. Exit to windows. Start the game again and the save is loaded correctly!
After this is done, you can revert your regional settings to previous settings (Slovak in my case) and the saves are working

My best Regards,
Astorian