NetStream OnMetaData error

I have this error:

on this code :

In another project, my class works well, but here it does not. Why?

Your video contains closed caption events, but you haven't registered an event listener to handle the "Show this line of text" event (OnMetaData), so the appearance of caption data is an uncaught exception.

Register an event listener, even if it does nothing, or use a video without captions.