Is there a limit to the number/size of playlists

After some research and some trial an error, I managed to identify a process of creating playlists. I keep my music in a hierarchical structure of folders, with genre at the top, then artist/composer, then CD (all my music is in .mp3 format ripped from CDs). I copy the genre folder to the Clip Sport Plus (with all its subfolders and .mp3 files). I then open up WMP and expose the “create playlist” section of the Play tab. I then drag the genre folder to the “create playlist” section and wait until WMP finds all the files and calculates the total play time. I then click on the File tab in WMP and select Save Now Playing List as, change file type to .m3u, change the file name to the desire name, select the Playlists folder on the player and click on save. This worked for the first several playlists I created. But I have two more that I want to create. I follow the same exact process for creating these playlists and they seem to execute without error. But when I eject the player and let it refresh, I find that the last two playlists are “empty”. I’ve tried this several times, but can’t get it to work. Anyone know what might be the problem? Is there a limit to the number of playlists or to the aggregate amount of space allotted to storing playlists?

Thank you,