xb_stream_read_chunk(): wrong chunk magic at offset 0x0
Would have preferred to answer using a comment, but I haven't enough points yet.
Disclosure: I work for Percona. I have put your question to our tech team, and they are not sure that you have created a xstream archive.  

There are examples here 

For xstream the backup would be something like this:

innobackupex --stream=xbstream /root/backup/ > /root/backup/backup.xbstream

and then the extract from backup.xtream would be something like this:

xbstream -x &lt;  backup.xbstream -C /root/backup/

If you need more discussion, that might be easier via the free Percona forum .