You have saved a backup of your image and settings from your DM500s and wish to restore it with with Dreamup.
When you flash an image with dreamup, you will be asked to perform a 'flash erase'. If
you were flashing a normal image you would normally say yes. If you are flashing a backup image, you should say no. When Dreamup performs a flash erase, it erases everything in the /var folder and replaces it with the contents of /var_init so you would lose all your backed up settings. You would have a flashed image but would have to configure everything again (or redo the flash the right way). If you select NO, Dreamup doesn't perform the procedure of replacing the contents and all backed up data and settings are preserved.
Enjoy