How are you computing the variables? i.e. what is the code for each?
From the above output, it appears that Energy, Correlation, Contrast and Homogeneity are all structs with fields matching their names (for example Energy.Engery=2.2724e-007). Entropy, on the other hand, appears just to be a double.
I think that this mixture of structs and doubles is true given the error message that is telling you that the code cannot concatenate structs and doubles (the conversion to struct from double is not possible).
Either all variables should be structs, or all doubles. And I think it makes more sense to have all as doubles since there doesn't seem to be any advantage to having structs with a single field whose name is the same as the struct.
