Am I infringing copyrights?

I have been experimenting with recording techniques and I placed
a couple of test recordings of my Steinway Model B Duo-Art on YouTube,
with the intention of asking like-minded enthusiasts for constructive
criticism of the audio quality.  However, YouTube have sent me the
following warning:

> Steinway Model B Duo Art Test Recording 2
>
> Your video may include a song owned by a third party.  For example,
> this might be a song playing in the background or someone performing
> a song.  To hear the matched song please play the video on the right.
> The video will play from the point where the matched content was
> identified.  Your video is available and playable.  Here are details:
>
> "Rhapsody in C major Op. 11. No 3 Capriccio Op. 16. No 3", musical
> composition administered by one or more music publishing rights
> collecting societies.

Where do we stand with regards to posting recordings [on the Internet]?
My assumption was --

a) buying a [music] roll gave me performance rights;
b) any copyright expired 50 years after the performer's and composer's
   death;
c) postings could be made if there was no commercial gain;
d) they've got the wrong piece of music anyway!

Does anyone know where we stand and how to respond?

The video can be seen by searching YouTube for "Steinway Model B Duo Art
Test Recording 2",  http://www.youtube.com/watch?v=3q2QNb_I-fk 

Regards,
Steve Greatrex
Plymouth, UK