I know the solution for your issue. I also encountered the same issue in recent past. I had the outside cameras attached to my Laptop. So I tried to switch off the external cameras Once my cameras were off my program worked. So it was a camera software that was using my port.
In your case I think you are trying to use the "Eclipse" and "Arduino" simultaneously. Because of this I think your "com4 Port" conflict is happening and as a result the upload was interrupted.
So to fix your issue you need to restart your laptop and after that try to open your "Arduino" first and then try to upload. And do not open your "Eclipse" at the same time.