Save operation fail on applyChangs call in Lightswitch html

Lightswitch Html Client:

Getting the mentioned error in below code.

Functionalities are 1. save as draft(save without validation) and 2. click on next(save and next page).

1. Save as draft.

myapp.AddFinState.Save_execute = function (screen) {
    try {
        isDraft = true;
        myapp.applyChanges().done(function () {
            //window.location.reload();
            //myapp.showBrowseRefresh(null, screen.UserID, screen.UserName, screen.RoleType);
        });

        //myapp.activeDataWorkspace.FSCPDB.saveChanges().then(function () {
        //    window.location.reload();
        //});
        alert("Your draft has been saved successfully.");

    }
    catch (e) {
        console.log("Error in AddFinState.Save_execute. " + e.description);
    }

};

2. Save & next page

myapp.AddFinState.SubmitNext_execute = function (screen) {
    try {
        //myapp.applyChanges().then(null, function fail(e) {
        //    msls.showMessageBox(e.message, { title: e.title })
        //});
        myapp.applyChanges().done(function () {
            myapp.activeDataWorkspace.FSCPDB.FinancialSurveyRecords_SingleOrDefault(screen.UserID).execute().then(function (data) {

                if (data.results[0] != null) {
                    myapp.showAddFinRecord(data.results[0], screen.UserID, screen.UserName, screen.RoleType);
                }
                else {
                    myapp.showAddFinRecord(null, screen.UserID, screen.UserName, screen.RoleType, {
                        beforeShown: function (addEditScreen) {
                            addEditScreen.FinancialSurveyRecord = new myapp.FinancialSurveyRecord();
                        }
                    });
                }
            })
        })
    }
    catch (e) {
        console.log("Error in AddFinState.SubmitNext_execute. " + e.description);
    }
};

Please help in rectifying with code snippet.

Regards,

Sham