Index Error must not exceed 28

I am working on the multi-component fixed-bed adsorption system. Currently the number of gases that I am dealing in the model is 5. However, whenever I am extending it to the 6th it is giving me the following error:

"Index exceeds the number of array elements. Index must not exceed 28."

Kindly guide me what I am doing wrong.

I have checked the code as well to sort any discrepencay but I haven't find one.

[Jan]

"I am working on the multi-component fixed-bed adsorption system" - Okay. Most likely the readers do not. We do not know, which model you use.

I assume, you are working with Matlab code. Then please post the code an a copy of the complete error message. Without seeing the code it is impossible to find the problem.