1. Try both passwords It should be the user and password on your QlikView server in there.
2. Do you need section access to open the app?
3. Is your path valid? go to access point and make sure qvp path is correct and the app opens with no issues.
4. Try creating an empy app on the qlikview server and connect to that to eliminate issues.
5. If the Qlikview app is on the same server as the nprinting then try using local connection.
some things to try and troubleshoot this.