The phrase "wert in error" can be synonymous with several other phrases. "Mistakenly believed" can be used to describe a situation in which someone thought something was true but later discovered it wasn't. "Incorrectly judged" describes a situation in which someone made a wrong decision or came to a wrong conclusion. "Misjudged" is another term that means to make an incorrect assessment or conclusion about something. "Wrongfully assumed" can be used to describe a situation in which someone made an assumption that later turned out to be untrue. Overall, these synonyms all indicate a situation in which someone was incorrect or misguided in their beliefs or actions.