64-bit C# applications can only run on .NET Framework 2.0 or above. When installing your development environment, you must ensure that either the 64-bit version of the .NET SDK or the full Visual Studio 2005 Professional package is installed on your 64-bit Windows host.
You must add a reference to the 64-bit version of the .NET API (Platform.Symphony.Soam.Net_64.dll) in your Visual Studio 2005 application project files; see the 64-bit Symphony DE samples for details.
Since 64-bit C# applications are only supported on .NET framework 2.0, you must use Visual Studio 2005 to build your 64-bit applications.
When compiling the samples for a 64-bit environment using Visual Studio 2005, you must use the solution files suffixed with 64.2005.sln or 64_2005.sln.