Building with mdtool - RestorePackages target error (nuget)

Hello,

I'm trying to use mdtool to build my xamarin ios project. My command:

mdtool -v build -t:Build "--configuration:Release|iPhone" ~/Desktop/MySolution/MyApp.sln

However I don't get very far.. The error:

Xamarin Studio Build Tool
Loading solution: /Users/admin/Desktop/MySolution/MyApp.sln
   Loading solution: /Users/admin/Desktop/MySolution/MyApp.sln
      Loading projects ..
Building Solution: MyApp (Release|iPhone)
   Building: MyApp.Business.Core (Release)

      Build started 2014-03-05 6:28:02 PM.
      __________________________________________________
      Project "/Users/admin/Desktop/MySolution/MyApp.Business.Core/MyApp.Business.Core.csproj" (Build target(s)):

        Target RestorePackages:
            Executing: mono --runtime=v4.0.30319 /Users/admin/Desktop/MySolution/.nuget/NuGet.exe install "" -source ""   -RequireConsent -solutionDir "/Users/admin/Desktop/MySolution/"
            The specified path is not of a legal form (empty).
      /Users/admin/Desktop/MySolution/.nuget/NuGet.targets: error : Command 'mono --runtime=v4.0.30319 /Users/admin/Desktop/MySolution/.nuget/NuGet.exe install "" -source ""   -RequireConsent -solutionDir "/Users/admin/Desktop/MySolution/"' exited with code: 1.
        Task "Exec" execution -- FAILED
        Done building target "RestorePackages" in project "/Users/admin/Desktop/MySolution/MyApp.Business.Core/MyApp.Business.Core.csproj".-- FAILED

      Done building project "/Users/admin/Desktop/MySolution/MyApp.Business.Core/MyApp.Business.Core.csproj".-- FAILED

      Build FAILED.
      Errors:

      /Users/admin/Desktop/MySolution/MyApp.Business.Core/MyApp.Business.Core.csproj (Build) ->
      /Users/admin/Desktop/MySolution/.nuget/NuGet.targets (RestorePackages target) ->

        /Users/admin/Desktop/MySolution/.nuget/NuGet.targets: error : Command 'mono --runtime=v4.0.30319 /Users/admin/Desktop/MySolution/.nuget/NuGet.exe install "" -source ""   -RequireConsent -solutionDir "/Users/admin/Desktop/MySolution/"' exited with code: 1.

         0 Warning(s)
         1 Error(s)

      Time Elapsed 00:00:00.5408160

The Nuget command is the culprit, specifically it looks like it's being passed certain blank parameters. Nuget package restore seems to work fine when I build this through Visual Studio on my Windows machine.

Anyone know why this is happening?