The Robbery - S1-E2
Character mistake: When Jerry is selling his couch to Elaine, he tells her to take it out of the door and leave - but since the arrangement is that she would move to his place, that does not make sense. (00:12:10)
The Robbery - S1-E2
Character mistake: At the end of the episode, the waitress introduces her next door neighbour, a hot redhead. After saying her line, she leaves, and George says "Nice to meet you..." and is stuck shaking hands with Carol, who he already met before and invited him to the party to begin with. (00:21:45)
Character mistake: Jerry is shopping with Vanessa; in the store there's a sign with a special offer for the salad bar, "À la cart", instead of "À la carte" (00:05:30)
Answer: The name is Delores. He shouts that name at the end of the episode. Then in a later episode, "The Foundation", he runs into her. And he repeatedly calls her Delores.