How can I multiply only ingredient amount and not crashing the mod (Coding Problem)

[nattanang]

This mod crash because all 3 types of ingredient input is multiply by local cost multiplier, causing crash in line 42 of the code.
My question is how can I multiply only "Ingredient Amount" input by local cost multiplier without crashing the mod
Thanks in advanced

[Natha]

For one of the ingredients, the "amount" field is not present. You need to make sure it is.