From ReactOS

Window Stations and SystemParamtersInfo

NtUserSystemParametersInfo will fail when not executed on an interactive WindowStation. SPI_SETXXX fails, setting LastError to ERROR_REQUIRES_INTERACTIVE_WINDOWSTATION, SPI_GETXXX fails, setting LastError to ERROR_ACCESS_DENIED.

References

• MSDN:Window Stations and Desktops
• MSDN:Window Stations
• MSDN:WinStationQueryInformationW