I figured out that the numeric values should be within quotations marks, but I do now have a similar problem. How do I index on the value of Job j that depends on value specified by the parameter ProductSKU(j).

If you make the set that the index belongs to a subset of Integers, you will not have to use the single quotes around it.

If you don’t do that, you will have to refer to the element by enclosing it in single quotes

Thank you for your reply @gdiepen, it is now working properly .