In Max, one unit is one inch. So I if your character is 6 feet tall, I would draw a box on the viewport with 72 in height to check and see which model is incorrect. Then just use a xform modifier to scale the character to the correct size. It is very hard to determine what is wrong at the point, may be the model made in max was not model to scale, or the conversion between software was the problem. To set the actual units, go into the System Units setup (by clicking the button there) and set the units there. Then re import the model. It will scale to the new system unit.