The errors don't matter (it's as you said: the unusual way the browser is loaded with HTML code). However the text there does make a difference.

The code you are using is searching for the text "Uploaded videos" but your version of YouTube is in Norwegian? and the text is "Opplastede videoer" so obviously the code never finds "Uploaded videos" and Nothing is returned.

Try using "Opplastede videoer" instead.