I have always received error 4001 (unknown error) when using Match. It seems to complete Step 1 and Step 2 but when Step 3 starts (uploading artwork and remaining songs) I get this error. It says it is a problem with iTunes Store. Has anyone else received this message and were you able to resolve it?
MacBook Pro (Retina, Mid 2012)
I was having similiar problems uploading songs to iTunes match. It turned out to be my internet connection. I happened to take my laptop to my parents' house, and iTunes Match worked perfectly, uploading all the songs that hadn't uploaded yet. My internet connection at home doesn't seem to be problematic, but I'm almost certain it was the issue. Try taking your computer to a friend's house and using their internet connection to upload your music.
error 4001 ???
