The empty weight of the 757-200 is 130875 pounds, so your ZFW cannot be 107500 pounds.

So the question is this: is the weight in you are entering pounds? Or kilograms? If you are entering kilograms when it needs pounds, the number is going to be too low. 107500 Kilos is about equal to 236997, so the figure you would need to enter would be 237.0, which sounds like it could be about right.

See my explanation on how to get it to display kilograms or pounds here: http://www.captainsim.org/yabb2/YaBB.pl?num=1321617333/3#3
Using the hybrid settings gives the weights in kilograms too.

Mine had no problems accepting 107.5 as the ZFW (even though the real ZFW was around 109.0).

Mark