cadf does not seem to be an inbuilt MATLAB function, and you give no information about how it is defined or the output that it returns. And you also don't give us the complete error message (which tell us the line), so we have to also guess where this error is occurring in your code.
I like guessing games, so lets try.
First you define
which means M_coint is a matrix of class double. Then if we assume that cadf returns a structure, then the line
will try to allocate that structure to M_coint.
Ouch! Allocating a structure to a double is an error! It does not work.