Nicole, I agree with you! Your weight for your height is perfectly normal. I thought that as soon as read your specs, but then I checked this http://www.nhlbisupport.com/bmi/ BMI calculator and it puts you right in the normal range.
Was the device meant for elite athletes? Did they have a weight loss product to sell? Regardless of their reasons, I think that their measuring device is grossly inaccurate! Yikes!
Your weight makes my 135 pounds on a 5' 1 1/2" frame ghastly overweight - and I would not consider myself obese either.
If you feel good, are healthy, and your clothes fit, don't worry. Enjoy life and be happy with your nicely functioning body!
Hugs and butterflies,
~T~