I've met the ghost of the Lord of the Manor in King's Quest IV. Like the other ghosts I've met, I've gone to the graveyard and dug near his grave to retrieve some object he's lost. Except that my shovel breaks. Is this a glitch in the game? Normally this only happens when I've dug in the wrong place, and a walkthrough guide online confirms that I'm digging near the correct tombstone. Has this happened to anyone else?

IIRC shovel only has right amount of uses before it breaks, so you can't miss the right spot at all. I hope that the OP has save before he started digging, because otherwise he has to restart the entire game.

Thanks, guys! I did save it before the first ghost, so I was able to go back and dig in the right places for all of them.