The licensing popup appears when COM reports that the ActiveX is running in "design mode". You shouldn't redistribute the .lic file with your application.In the VNC Manager we also using dynamically created ViewerX instances as part the VNC Thumbnails view feature. I think you should add BeginInit() and EndInit() calls to your code. In C# the code should look like this:
AxViewerX.AxCSC_ViewerXControl objVNC = new AxViewerX.AxCSC_ViewerXControl();
objVNC.BeginInit();
//setup ViewerX properties here
PanelMain.Controls.Add(objVNC);
objVNC.EndInit();