Installing ActionML's PredictionIO

I executed the "Method 1: Quick Install" step as described in http://www.actionml.com/docs/pio_quickstart .

At the "Starting PredictionIO setup" step I see these warnings.

tar: Ignoring unknown extended header keyword 'SCHILY.nlink'
tar: Ignoring unknown extended header keyword 'SCHILY.dev'
tar: Ignoring unknown extended header keyword 'SCHILY.ino'
tar: Ignoring unknown extended header keyword 'SCHILY.nlink'
tar: Ignoring unknown extended header keyword 'SCHILY.dev'
tar: Ignoring unknown extended header keyword 'SCHILY.ino'
tar: Ignoring unknown extended header keyword 'SCHILY.nlink'

I don't know what to make of it, but it doesn't inspire confidence.