1) Has this plant bloomed before? Sometimes a young plant will throw a blind sheath or two before it brings one to flower. (I have buds now on a plant that has done that twice in the past year.)
2) Some catts bloom off of dried sheaths. I have only one that does that, but was quite glad I had left the sheaths alone as I had been advised.
There are probably more reasons, but I think those are the main ones.