I checked with the producers, and they reiterated what joelgundam01 in that it sounds like your DVD player setting needs to be changed as it isnt recognizing the aspect ratio correctly.
Are there any other settings for aspect ratio? 4:3 should be the one you are looking for, though.
DVD players usually only three ratio options.
I suggest trying each of the settings (including 16:9 Anamorphic) and see if one of them fixes the problem. We know that 4:3 Letterbox is out of the question. However, I don't know what the default setting was on Manheim's player. For all we know, it was already defaulted to 4:3 Letterbox.
FWIW, when I was using a SD TV (all the way until 10/30/2010), I had my DVD player set on 16:9 Anamorphic (fit to screen). I experienced some stretching, but I didn't see any black bars or cropping with this option. As long as the DVD supports the anamorphic feature.