Minimize Problem in MC 15

Hello folks,

I have here a problem with the Minimize function. MC claims that a variable is not defined although it is.

Has anybody a clue where I went wrong?

Thanks in advance

Raiko

P.S.

I'm using MC 15 on a 64 bit Win 7 machine.

P.P.S.

I know that the equation sigma is lengthy ;-) in it's definition but in order not to get lost in the many nagle definitions I decided to write each and every into the function.