The following error may occur:
Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.

This often indicates that the license file is not embedded in the application. Please follow the steps given below:

• Include the license file in the project as Embedded Resource
• Now recompile the application, it should work in windows service