Automatisierungsserver kann Objekt nicht erstellen

[kai]

i have designed a infopath application. In the application i need to
open a new form. In the Preview form is works. but as i really start
it, the error message comes:Automation server can't create object

my problem code:
var oApp = new ActiveXObject("InfoPath.Application");
var oXDocumentCollection = oApp.XDocuments;
var oXDocument = oXDocumentCollection.Open(...);