BitsDownloaderProviderData

To make a .NET structure works on 64-bit machine, a refence-type
field should has offset of multiples of 8 bytes ( as well as having 8 bytes'
length), but the structure BG_BASIC_CREDENTIALS looks
like:

    [StructLayout(LayoutKind.Explicit, Size
= 8, Pack = 0)]

    internal struct
BG_AUTH_CREDENTIALS_UNION

    {

        [FieldOffset(0)]

        public BG_BASIC_CREDENTIALS Basic;

    }

    [StructLayout(LayoutKind.Explicit, Size = 8,
Pack = 0)]

    internal struct BG_BASIC_CREDENTIALS

    {

        [FieldOffset(0)]

        [MarshalAs(UnmanagedType.LPWStr)]

        public string UserName;

        [FieldOffset(4)]

        [MarshalAs(UnmanagedType.LPWStr)]

        public string Password;

    }

That's why we
get that exception.

You may report a defect to the dll owner, or, if you can modify the
source code, just refine the BG_BASIC_CREDENTIALS struct
to:

    [StructLayout(LayoutKind.Explicit, Size = 16,
Pack = 0)]

    internal struct
BG_AUTH_CREDENTIALS_UNION

    {

        [FieldOffset(0)]

        public BG_BASIC_CREDENTIALS Basic;

    }

    [StructLayout(LayoutKind.Explicit, Size = 16,
Pack = 0)]

    internal struct BG_BASIC_CREDENTIALS

    {

        [FieldOffset(0)]

        [MarshalAs(UnmanagedType.LPWStr)]

        public string UserName;

        [FieldOffset(8)]

        [MarshalAs(UnmanagedType.LPWStr)]

        public string Password;

    }

참고 : http://msdn.microsoft.com/en-us/library/aa362789(VS.85).aspx