(SOLVED) Gui not accepting items

I made a gui bound to a custom block, it has 1 slot with an id of 00, and I bound the gui to accept id + 1 = 1. But it will not allow me to place any item in the slot. Disable player using slot is turned off, and there are three buttons in the guis as well. I tried remaking the gui and rebuilding the code, but it didn't work. Please help. TIA

EDIT: As it turned out, the gui button procedures were broken, and had to be disassembled and put back together. In the end, it worked.