FileTransfer returning error code null with cordova 3.0.0

should help you out Serverside script was wrong... naturally I should have figured that out given the obvious FileTransferError.FILE_NOT_FOUND_ERR error message. Apologies for wasting everyone's time and thank you for making the effort.

it helps some times I'm developing a mobile app for iOS and Android using Cordova and Ionic Framework. There needs to be 'Send Photo' and related functionality, and I'm using Cordova's FileTransfer to do this. , Maybe late but I've kinda fixed it.
In my view file I use:

<input id="file" name="file" type="file" onchange="angular.element(this).scope().addFile(this)" class="upload" accept="image/*" capture="camera"/>

$scope.addFile = function(item){

        function uploadComplete(evt) {
            /* This event is raised when the server send back a response */
            $scope.imgId = JSON.parse(evt.target.responseText).data;
            $scope.$apply();
            $http.post($rootScope.baseServerUrl + 'Members/changeAvatar', {attachment_id: $scope.imgId}).success( function (response){
                console.log(response);
                $scope.User.attachment_id = $scope.imgId;
                $scope.$apply();
            });
        }
        function uploadFailed(evt) {
            alert("There was an error attempting to upload the file.")
        };
        var updateImage = function (element) {
            $scope.$apply(function() {
                $scope.theFile = element.files[0];

                var formData = new FormData();
                formData.append("file", $scope.theFile);

                var xhr = new XMLHttpRequest()

                xhr.addEventListener("load", uploadComplete, false)
                xhr.addEventListener("error", uploadFailed, false)
                xhr.open("POST", $scope.baseServerUrl + "media/Attachments/add")
                xhr.setRequestHeader("Accept","application/json")
                $scope.progressVisible = true

                xhr.send(formData);
            });
        };
        updateImage(item)
    }

wish of those help The problem was caused by an upgrade of Cordova from a previous version.
The path of local files was not properly identified: .fullPathis now obsolete and should be replaced by .toURL().

fixed the issue. Will look into that further Turns out this was that kit kat version bug that was happening for a while. i restricted my version of android to 21, and all my woes went away.
thank you @aorfever for your answer, it is exactly what i was doing, but ended up being something out side of the actual functions i was calling that was the issue!

will help you Finally this simple solution works for me.
UPDATE After Changing the Code in App controller and Webapi Controller Every thing working like a charm and images are start saving on server via API.

 uploadOptions.httpMethod = "POST";
                    uploadOptions.headers = {
                        Connection:"close"
                    };

var httpPostedFile = HttpContext.Current.Request.Files["file"];