@retropieting I know this topic is quite old, however I had exactly the same issue and was able to fix it so I thought I would share it here for others with the same problem.
The issue is that the Scraper included the "Mame2003" game folder (for want of a better term) as a game to be scraped. The lines it adds (Unknown, Unknown, Unknown, Players) relates to Developer, Publisher, Genre and # of players.
The way I got round it was to boot into retropie, then press select/options (on the controller) when Highlighting the Mame2003 folder and chose to edit the games meta details. I then typed a unique value for the Developer and saved it. Then when I looked in the gamelist.xml file I could see the entry right at the bottom of the file under the <folder> tags. I then edited this file to include some blurb around the emulator itself, gave it a first release date (5th Feb 97 if I remember correctly) and added a nice image to round it off.
I do wonder if you could correct the issue permanently by deleting the folder section from the xml file, but I quite liked the summary.
Hope this helps someone else!