Hi @lizv,
I would definitely suggest that you contact your teacher about this issue via whatever method they have made available to you (email, phone, office hours, etc). When you see a message like that, it usually means that either your teacher just uploaded the files, or that there was an issue with the file upload and the system can't figure out how to play the audio/video. In the first case, if you wait maybe 30 minutes or so, the message would go away. When it persists for a long time, it's likely the second case and your teacher will need to try uploading the files again for them to play.
I hope this info helps, even though it's a bit late.
-Chris