playlist error: can't download

Hello,

Please test out the following playlist link: https://www.youtube.com/playlist?list=PLGR7sDvLxCLqiDd5V2MgZrHvg5hBzHBfK

It is a very large playlist, and although some mp3's do download, there are many that don't and display the following error message: "Error: can't download"

I hope you can come up with a fix.

Thanks!