In the LiveCycle Adminui you can go to Services/Applications and Services/Service Management screen and locate your service. Once you have it click on your service to bring up the details about your service (see screen shot below):
In the 1st red area you can turn security off for yor service (this will stop the dialog from poping up in Reader). Then in the 2nd red area you need to indicate which user will be used to run this service. You cannot use the Invoker anymore because you are executing this service annonymously. I would suggest that you run as "System".