My project does not work for Windows 8.1 x64?

Hello,
I want to change the lock screen image programmatically for Windows 8.1 and built the win32 project using the API 'SetLockScreenFromFile', it works well for Windows 8.1 x86, but it seem not work for my Windows 8.1 x64, even i can see the lock screen image has been changed in PC Settings. Can anyone help me to test on your x64 Windows 8.1? thank you.

Download link
https://onedrive.live.com/redir?resid=4D04CDB4562A8258!3992

Thank you, is your OS Windows 8.1 x64? Maybe my OS has some problems if your system is X64.

Thank you very much.

Another problem, why my lock screen will not show at once after clicked the lock button (Win + L), instead of the login screen, the lock screen will show after one minute, how to show the lock screen at once?