Plot hole: After Little John bores a hole in the bottom of the treasure box, several gold coins fall through the hole. The four rhinos holding the box should have noticed it becoming lighter.
Continuity mistake: In the opening sequence when the Sheriff's posse are chasing Robin and LJ through the woods, pay close attention to the posse [weasels, I think?]. When they first pop up behind the bushes, there are five of them. Later, when they're clustered under the tree that RH and LJ are hiding in, there are six of them. Finally, when they exit stage left over the log-bridge, seven creatures are seen.
Continuity mistake: During the battle part of the archery tournament (around the part when the Rhinos, Lady Cluck and Little John are in the tent), Little John looses the lighter colour in the front of his snout, making his whole face the same shade of brown (precisely at 46min29sec). His face then goes back to normal (darker near the eyes, lighter at the snout)half a second later.
Continuity mistake: In the scene where Robin and Little John are disguised as fortune tellers, Little John "kisses" the three stones out of the rings on Prince John's left hand. In the rest of the scene that left hand changes backwards and forwards between shots with having no rings at all to having rings with only the claws. (This is not the same hand Robin Hood takes the ring from).
Continuity mistake: After Robin and Little John kiss Prince John's hands and steal the jewels, Robin pretends to tell the Prince's fortune. Little John produces a ball full of fireflies and the prince tries to touch it, but Robin hits his hand away. The prince looks at it in shock - but surely he would have noticed the jewel missing from his ring.
Continuity mistake: In the scene where Robin Hood is talking to Little John and Friar Tuck about entering the archery tournament, Robin Hood jumps up on a wooden platform and is wearing a quiver with two arrows on his back. The quiver vanishes in his next shot where he fires an arrow at a pan hanging from a tree.