Step 1: Identifying the error.
The error in the sentence is the phrase "has been worked." The verb "worked" is incorrect in this context because it suggests the passive voice, but the intended meaning requires the present perfect tense in the active voice. In active voice, we use "has worked" instead of "has been worked."
Step 2: Correct sentence.
The correct sentence is She has worked in this office since 1996. The present perfect tense is appropriate here to indicate an action that started in the past and continues to the present.