In your question, you say that you are seeing this error message — which refers to the AMPL objective function Total_Cost:
error processing objective Total_Cost:
no value for CCT[1]
The most common reason for this error is that you have defined a parameter CCT in your model (using a param statement), but you have not provided any data values for the parameter.
To get more help, reply with copies of your files attached. (Use the
icon to attach files.) With that information, it may be possible to give more advice on writing the objective and the CCT_k = constraint.