I know what you did wrong, when burning with Imgburn make sure you tick the box marked "Don't update IFO/BUP files" in the Layer break position pop up box that appears after you click burn . After that, you should be fine! (I was also having that problem earlier, but after I did that, the DVD works fine)
Also, copy both the Video_TS and Audio_TS folders from the mounted drive, then burn those.