Procedure missing dependency x on run

HI All,

I am trying to make block where it trades one item with another item. I created a block, a GUI, and a procedure for the job.

with the procedure. I used the furnace template code as a base for my logic. it basically takes item from input slot (0) and put another item to output slot (1), with the item count check logic, etc. It compiles ok and starts up the test game ok.

but when i open the GUI in game and place the items into the input slot, the console logged that it failed to load the dependency X, and then failed the procedure.

so i guess i didnt provide the required value x, y, z into the procedure?? but i thought these are automatically available in any procedures?

Could someone point me to the right direction please?

Thanks