Rc is empty (it gets initialised as a global variable but nothing is assigned to it), but it's used in your calc=... calculation.
Was this intentional?
The problem here is that anything multiplied by an empty [] will return []. And any non-empty matrix divided by an empty matrix will cause an error.
The final part of your calculation:
kfiler/(1+2*(kfiler*Rc/d))
Is one such part. kfiler is not empty, but Rc (and consequently (1+2(kfiler*Rc/d))* is empty.
You'll get the same error if you type in:
100 / []
One small suggesion: break up your calculation into a few lines. Otherwise it will be a complete nightmare to debug because all error messages will point to this one huge line (which doesn't help you track them down)
