I'm trying to figure out what went wrong for you and devise a solution because you ought to be able to use date ranges without problem as I do in FTMM2.
It looks like you've changed the preferences for how dates are displayed and possibly entered. Did you do that before you first loaded the file into FTMM2? What are your Dates & Names preferences (a screen shot would be helpful)?
Speaking of migrating your family tree, how did you do it? Did you use the migration tool or go through an Ancestry member tree?
If you customized your date format in FTM 2012 too, what settings did you use?
Would you consider privately sending me your FTM 2012 file so that I can use it to try to work this out?