When the Three Stooges are talking to Mr. Graves, Charles Middleton, his butler, is standing at the far end of the desk. Next scene, he's no longer there.
The Stooges are told that Mr. Graves must know the exact time in every country, but the clocks on the walls all have different times.
When Curly was repeatedly punched with boxing gloves out of the bookcase secret panel and then Moe comes through opposite side, the back of the bookcase is solid. He couldn't punch through.
At one point Moe tells Larry and Curly they need to separate. He intends to say either, "Spread out," or "split up," but instead says, "Spread up."