If you're on an XP machine, try this. It helped me out:
Go Control panel, System, Hardware, device manager. Click on Disk Drives.
If you find anything labeled ChinaChimp or Jz474 Rockbox-whatever, right-click and uninstall. your computer may need to reboot after that. Let it.
Hold reset-B on the Dingoo to put it into USB mode as usual. Plug it in. Now a device wizard or a dialog box should pop up when you do that (hopefully the wizard), so CLICK IT. CLICK CONTINUE. CLICK ADVANCE. This will cut off your auto-install and stop windows from thinking your machine is anything other than what you want it to think it is.
Now, in the device install wizard (Holy Tesla help you if it's anything else) select manual, go to the dual install folder, load the driver from there and try the terminal codes again. If that fails try getting the dual boot packets from somewhre around here, like the excellent FAQ here:http://boards.dingoonity.org/dingux-help/dingoo-and-dingux-troubleshooting-and-faq-guide/
That's what got me to the next step.
If you're not on a Windows XP machine, disregard everything I'll ever say.
Okay. Best of luck!