Problem: the output field displays NaN even if input is a number!

I have five input textfields that is used in a formula. The problem is the fifth input field (in5). When I typed in a nnumber with a decimal (0.55) the output fields displays NaN. Also if I placed in anegative number the outputs will have NaN. The other four input field (in1-in4) doesn’t have this problem. I tried place a

in5 = Number(in5);

but it doesn’t work!

Anybody have any idea how to go about this problem?

Thanks.