Unable to download you tube music

I purchased plus today.  I finally got it activated.  Have several differnet errors after trying to delete and reinstall.

1.  I go to You tube and copy the link.

2.  I open downloader

3.  Paste the URL in box at the top

4.  Get a message "video is being fetched.  Please wait ."

5.  Next message says, "Object reference not set to an instance of an object"

I purchased this product a few years ago and loved it.  However, now I am thinking about getting my money back with Plus.