It looks like there's variable definitions missing here.
Debugging code is a skill and not an easy one to learn. In the code you attached above you are generating a huge list of Interpolations. Then you are trying to find the maximum value for each of them individually.
If you are having trouble, then do this: Create only one of the interpolating functions. Then find its maximum value. The plot it and it's maximum value.
When you get stuck, step back, find a simpler version of the problem and then work on it.
