Just to clarify what Duplicate Formulas errors mean, when you open a file and you get that error, it means that the file contains two (or more) references to the same morph (usually), and daz tells you hey, I found Duplicate Formulas. I am not sure how or why daz sometimes saves Duf files with duplicate formulas, because I doubt creators add them on purpose, it's probably a glitch/bug.
Duf files should contain only one reference per morph. The ultimate solution is to edit the duf file in a text editor and search for the formula/morph, and usually it's found referenced twice (or more), then delete all but one of the references. Be carefull with that, make sure you do not delete any extra "{" or ",", or leav any extra ones either.
Another problem is that sometimes they have different values/settings for the same morph. In that case I make two copies of the offending duf file, one with each of the duplicate formulas, then check them out in daz and see the difference, and decide from there which copy I would keep, if not both (or all).
