It's fine. Ignore them, they're normal.

The ReiserFS one is because the music partitions on the empeg don't use ReiserFS but Ext2. The Rio Central however does and shares some of the same code so that is why it's complaining.

The VBR one is because your MP3 files are Variable BitRate but don't have a valid VBR header which allows you to seek properly. It'll play but seeking will be a little strange. It's nothing to do with the player or Hijack.