Cannot handle the request because a modal dialog or alert is active

hi all

i try to use indesign product sdk CS5 using com object to open and edit document with asp.net

this error appear to me in this part of my code

            InDesign.Application indApp = (InDesign.Application)Activator.CreateInstance(InDType, true);

           indApp.ScriptPreferences.UserInteractionLevel = idUserInteractionLevels.idNeverInteract;

            InDesign.Document objDoc = (InDesign.Document)indApp.Open(cstrInddFile, true, idOpenOptions.idDefault);

Cannot handle the request because a modal dialog or alert is active.\\\   at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData) at InDesign.ScriptPreference.set_UserInteractionLevel(idUserInteractionL evels ) at _Default.Button1_Click(Object sender, EventArgs e)

thanks advance