Which of the following have made an error of principle?

Svetlana - Recorded a payment of £530 in the company's expenses account rather than its sales account.

Jim - Recorded a payment of £1,000 in both the company's expenses account and the sales account.

David - Forgot to record a payment of £50 in the company's sales account.

Jean - Recorded a customer payment as £120 when they actually paid £150.

Janet - Recorded the payment made by one customer in another customer's account.