Music Match is missing some of my songs

I finally got around to creating a music server on my home network because my kids kept complaining about only seeing purchased music and my files were scattered across multiple hard drives. So I decided to just download all the files directly from iTunes onto the new (to me) Mac Mini used as a server. I have about 17,000 songs/files that have been uploaded through Music Match. There are now about 20 songs that iTunes gives me an (err = -50) code on and do not download. These songs have been up in Music Match since at least late 2010, and I know I have played them before and even iTunes tells me I have. In fact I just double checked and they will play on my phone - they just won't download?

I am attaching screenshots to hopefully better explain.