Call to undefined function xspf_playlist_node_thumb_delete() in xspf_playlist_thumb.module on line 331

Title says it all... what happened to the xspf_playlist_node_thumb_delete() function?!

ps. I put the version as 6.x-1.0-alpha1, but actuall I'm using DR~UPAL-6--1 from CVS - why not enable your -dev releases?!