To solve the problem, add the title parameter:
title=song 1|song 2|song 3
To answer your other question, the playlistrss parameter is for if you have a podcast or something, and you constantly want to change the music. In that case, you could create an XML file containing the following (or something similar):
<?xml version="1.0"?>
<rss version="2.0">
<channel>
<title>playlistrss</title>
<item>
<title>song 1</title>
<enclosure>
http://flash-mp3-player.net/medias/another_world.mp3</enclosure>
</item>
<item>
<title>song 2</title>
<enclosure>
http://flash-mp3-player.net/medias/another_world.mp3</enclosure>
</item>
<item>
<title>song 3</title>
<enclosure>
http://flash-mp3-player.net/medias/another_world.mp3</enclosure>
</item>
</channel>
</rss>
And so on and so forth, whenever you want to change the list, you change the RSS file. This is useless is you don't update it often though, otherwise just use the title parameter mentioned above.