Debugging F# in Xamarin Studio 4.0.3 throws an err

I have installed Xamarin Studio 4.0.1 on Windows 8 x64 from http://monodevelop.com/Download . When I ran Xamarin, it got updated to 4.0.3. I have installed F# bindings. I have created new F# console project. When I run it, it works fine. When I set a break-point and run it, I get the following error. Any idea, why that happens?

System.Runtime.InteropServices.COMException (0x80070032): The request is not supported. (Exception from HRESULT: 0x80070032) at Microsoft.Samples.Debugging.CorDebug.NativeApi.ICorDebug.CreateProcess(String lpApplicationName, String lpCommandLine, SECURITY_ATTRIBUTES lpProcessAttributes, SECURITY_ATTRIBUTES lpThreadAttributes, Int32 bInheritHandles, UInt32 dwCreationFlags, IntPtr lpEnvironment, String lpCurrentDirectory, STARTUPINFO lpStartupInfo, PROCESS_INFORMATION lpProcessInformation, CorDebugCreateProcessFlags debuggingFlags, ICorDebugProcess& ppProcess) at Microsoft.Samples.Debugging.CorDebug.CorDebugger.CreateProcess(String applicationName, String commandLine, SECURITY_ATTRIBUTES processAttributes, SECURITY_ATTRIBUTES threadAttributes, Boolean inheritHandles, Int32 creationFlags, IntPtr environment, String currentDirectory, STARTUPINFO startupInfo, PROCESS_INFORMATION& processInformation, CorDebugCreateProcessFlags debuggingFlags) at Microsoft.Samples.Debugging.CorDebug.CorDebugger.CreateProcess(String applicationName, String commandLine, String currentDirectory, IDictionary`2 environment, Int32 flags) at MonoDevelop.Debugger.Win32.CorDebuggerSession.OnRun(DebuggerStartInfo startInfo) at Mono.Debugging.Client.DebuggerSession.<>c__DisplayClassc.b__a()

The problem with the Win32 Debugger is that we do not support x64 debugging. Try debugging the Application in 32bit and it will work.

We need to implement remote debuggin, aka spawning a 64bit debugger so we can debug a 64bit app. We use MDbg as a backend.

Also check: http://blogs.msdn.com/b/jmstall/archive/2006/03/08/debugging-cross-platform.aspx