You were right it was DIM 100. I deleted that and BOOM it worksin your worldsave you have a few different subfolders
DIM1 contains the End (dimension id 1)
DIM-1 contains the Nether (dimension id -1)
Look up in your Extra Utilities config what the dimension id of the Deep Dark dimension is and then find and delete the folder named:
DIM<dimension id you just found>
I think I remember it being DIM-100, but you can never be too sure.