SSIS Script Task - No Interface Supported

问题

Purpose: I have an SSIS Solution with various packages, one set of these packages is currently created with a package per table due to them having different structures. The aim is to create a template package (done), update variables/table names (done), reinitialise and re-map columns, execute package for each table.

Problem: So, as you can tell, I'm up to the point that i need to reinitialise but I am unable to get to the data flow task and keep getting this error:

No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE))

When I run this code:

    //// Get Data Flow task 
    TaskHost tHost = pkgOut.Executables[0] as TaskHost;
    MainPipe dataFlowTask = (MainPipe)tHost.InnerObject;

The code that I am using is below:

    public void Main()
    {
        // Set Project Variables
        List<string> pkgVars = new List<string>
        {
            @"pPR_SSIS_Catalog_Server",
            @"pPR_SSIS_Catalog_Project",
            @"pPR_SSIS_Catalog_Folder"
        };

        // Get Package
        String pkgLocation = @"C:\PATH\TO\TEMPLATE\PACKAGE\a_Load_SAP_Template.dtsx";
        Application app = new Application();
        Package pkgIn = app.LoadPackage(pkgLocation, null);
        String pkgName = "DynamicPackage";

        // Add Connections (cos they're project connections and aren't stored in package)
        ConnectionEnumerator allConns = Dts.Connections.GetEnumerator();
        while ((allConns.MoveNext()) && (allConns.Current != null))
            pkgIn.Connections.Join(allConns.Current);

        // Convert new package to XML so we can cheat and just do a find and replace
        XmlDocument pkgXML = new XmlDocument();
        pkgIn.SaveToXML(ref pkgXML, null, null);

        // Replace strings
            // Set SAP table
            String pkgStr = pkgXML.OuterXml.ToString();
            pkgStr = pkgStr.Replace("#SAP_SRC_TABLE#", "MyF-ingSAPTables"); // Replace SAP Table Name

            // Set Project Variables references == values  -- REMEMBER TO CHECK FOR INT PARAMS zzz
            foreach (string var in pkgVars)
                pkgStr = pkgStr.Replace(@"@[$Project::" + var + @"]", @"""" + Convert.ToString(Dts.Variables[var].Value) + @"""");

        // Convert back to XML
        XmlDocument newXML = new XmlDocument();
        newXML.LoadXml(pkgStr);
        Package pkgOut = new Package();
        pkgOut.LoadFromXML(newXML, null);

        //// Get Data Flow task 
        TaskHost tHost = pkgOut.Executables[0] as TaskHost;
        MainPipe dataFlowTask = (MainPipe)tHost.InnerObject; // THIS IS WHERE THE CODE ERRORS

        new Application().SaveToXml(String.Format(@"D:\PATH\TO\SAVE\LOCATION\{0}.dtsx", pkgName), pkgOut, null);

        Dts.TaskResult = (int)ScriptResults.Success;

    }

I have tried:

Removing everything but the data flow
Recreated a blank data flow
Recreated the package
Made a package in the script and created the data flow (this works but when i open the package, the data flow does not appear...might have added it wrong but it can see it when I run the TaskHost section)

I am not sure what else I can try, I have seen information that I might need to re-register some .dlls but I do not have admin access and I'd prefer not to go through the hassle for something where I do not know whether it will work.

Any help would be appreciated.

Thanks,