I have the talkative pet addon for mBot and have the same problem as described in another (locked) post:
The dog program seems to upload fine, the tail wags and the wheels move back and forth but the audio player doesn’t work. I verified the SD card has the correct files, and tested the audio player with a separate small program. The dog program is also supposed to use the ultrasonic and light sensors but both appear to be unresponsive.
I have tried using the test case programs available from both of these links: