Can't build C# in ST2

Question

I've installed Sublime Text 2 and I'm wishing to use it in conjuction with C#, but for some reason I can't build my code. The error I'm getting:

Project "D:\PannariBranch\Dropbox\dev\build.cs" on node 1 (default targets).
D:\PannariBranch\Dropbox\dev\build.cs(1,1): error MSB4025: The project file could not be loaded. Data at the root level is invalid. Line 1, position 1.
Done Building Project "D:\PannariBranch\Dropbox\dev\build.cs" (default targets) -- FAILED.

Build FAILED.

"D:\PannariBranch\Dropbox\dev\build.cs" (default target) (1) ->
 D:\PannariBranch\Dropbox\dev\build.cs(1,1): error MSB4025: The project file could not be    loaded. Data at the root level is invalid. Line 1, position 1.

0 Warning(s)
1 Error(s)

Time Elapsed 00:00:00.03
[Finished in 0.8s with exit code 1]

This is my build configuration:

{
"cmd": ["msbuild", "$file"],
"working_dir": "${file_path:${folder}}",
"file_regex": "^\\s*(.+?)\\(([0-9]+),?([0-9]+)?\\):\\s*(.*) \\[",
"shell": true,
"selector": "source.msbuild",
"windows":
{
    "path": "%PATH%;%WINDIR%\\Microsoft.NET\\Framework\\v4.0.30319;%WINDIR%\\Microsoft.NET\\Framework\\v3.5;%WINDIR%\\Microsoft.NET\\Framework\\v2.0.50727"
},
"linux":
{
    "cmd": ["xbuild $file"]
},
"variants": [
    {
        "cmd": ["msbuild", "/m", "$file"],
        "file_regex": "^\\s*\\d*>?\\s*(.+?)\\(([0-9]+),?([0-9]+)?\\):\\s*(.*) \\[",
        "name": "Parallel Build",
        "linux":
        {
            "cmd": ["xbuild /m $file"]
        }
    },
    {
        "cmd": ["msbuild", "$file", "/p:Configuration=Debug"],
        "name": "Debug Configuration",
        "linux":
        {
            "cmd": ["xbuild $file /p:Configuration=Debug"]
        }
    },
    {
        "cmd": ["msbuild", "$file", "/p:Configuration=Release"],
        "name": "Release Configuration",
        "linux":
        {
            "cmd": ["xbuild $file /p:Configuration=Release"]
        }
    }
]
}

All help would be much appreciated. :)