"Music is certainly an important part of The Tempest," says Professor Lindley. "It is an important means by which Prospero exercises his power, and it moves the characters round the stage. It puts the characters to sleep, it wakes them, it cures them of their madness, it propels the action."
The error in this sentence is a A) pronoun-antecedent voice agreement error. But it should be noted that this has become more standard usage in common dialogue.
