Can't add power-up in N.I.L.E.

[grenadier501]

Hello all, it's been a while since i used NILE to make maps, but today i tried something that i never tried, Power-ups placement, it just doesn't let me do it!

An error message keeps popping up saying this: "An object of the requested type could not be created" why is this? any way to solve it? i've been thinking placing any working item, saving the project as .NPJ, editing the file with notepad, and try to replace the ID of that item to a power-up ID, but i'm not sure if that would work :/