The danger is injury. When I was a bit heavier I started pushing myself too hard and suffered a torn calf muscle. You do NOT want to do that. I ended up re-injuring and then couldn't exercise for ages.
So until your joints get used to it, don't run every day. Every other day is cool. Mix it up a little bit, maybe if your gym has pilates classes - this is great for strengthening your core and other muscles which can help prevent injury.
Personally I don't think I could go to the gym every day, but I do try to exercise every day and then have one 'light' or rest day each week. I run, I go to rugby training, and I go to Bikram yoga one day a week, but I also go to the gym.
Lose 25lbs by 15 April (10 Mar)
Get to 100 kg (220) by 1 May (7 Apr)
Be 205 by race day - 14 July
One-derland by 1 Sept