opening Symbolic URL in Open UI

 We are in the process of upgrading siebel 8.1.10 version (Open UI) and we have a major functionality that is not working. We have a document generation process in which under a button click we invoke a symbolic url to open the document using pop up applet.
this is the code which we try to invoke the pop up applet.

if (MethodName == "Generate")
{
var oServiceAF = TheApplication().GetService("SLM Save List Service");
var inputPropAF = TheApplication().NewPropertySet();
var outputPropAF = TheApplication().NewPropertySet();
inputPropAF.SetProperty("Applet Name","ST CPL Letter Popup Applet");
inputPropAF.SetProperty("Applet Mode","6");
inputPropAF.SetProperty("Applet Height", "700");
inputPropAF.SetProperty("Applet Width", "700");
oServiceAF.InvokeMethod("LoadPopupApplet", inputPropAF, outputPropAF)