Factual error: When Venonat uses Stun Spore, Ash tells Bulbasaur to use Whirlwind. Bulbasaur just blows the powder away with his mouth, but he doesn't use the Whirlwind attack. He can't learn Whirlwind in any of the games, and what Whirlwind is supposed to do is to blow the opposing Pokemon away. Ash could have just as easily told Bulbasaur to blow it away, but he instead chose to tell him to use a move that he can't possibly learn. The only Pokemon that can learn Whirlwind are either Flying types or Bug types; i.e., Pokemon with wings (with the exception of Makuhita and Hariyama, which weren't introduced until generation III, and did not exist at the time this episode aired). In The School of Hard Knocks (Season 1, Episode 9), a character mentions information regarding a Pokemon's levels, attacks, and information which is taken straight out of the game, so it's very clear that Bulbasaur should not be able to use Whirlwind.Knever
Other mistake: The Pokemon Exeggcute is shown evolving in to an Exeggutor naturally. But the Pokemon Exeggcute can only evolve into an Exeggutor with the use of a leaf stone. In the Japanese version, there is a mention that something in these woods causes Exeggcute to evolve without using the Leaf Stone (when Exeggcute evolves, James even mentions that there is no stone). However, as this was skipped in the English version, it creates a plot hole.
Character mistake: When Team Rocket first sees Mandy doing his magic tricks, he produces a bunch of Pidgey. Meowth says "I like those Pidgeotto." He's dealt with Ash's Pidgeotto on numerous occasions, so there's no reason that he shouldn't be able to tell the difference.Knever