SQL Server CE v4 on Windows 8

I built the app using SQL Server CE 4.0 and it runs just fine in Windows 7.0 dev machine, but got the following error message running it in Windows 8 (x64 version, Lenovo All-In-One Horizon 27' HW platform):

Is not a valid Win 32 application (Exception from HRESULT: 0x800700C1)

In app directory I can clearly see the

System.Data.SqlServerCe.dll

and all other 7 DLLs:

Sqlceca40.dll    Sqlcecompact40.dll     Sqlceer40EN.dll  
Sqlceme40.dll    Sqlceoledb40.dll       Sqlceqp40.dll      Sqlcese40.dll

taken from C:\Program Files\Microsoft SQL Server Compact Edition\v4.0 root directory and included in the app dir as per recommendation at: http://msdn.microsoft.com/en-us/library/vstudio/aa983326%28v=vs.110%29.aspx .

Other settings:

• Configuration Platform: Any CPU Target Platform: x86 Setup
• TargetPlatform: x64

Any idea on what went wrong and how to fix it? Thx.