Hi,
just for info
for those of u having my same problem (still not solved using Open Office) I have
installed the LibreOffice suite RC1 from here:
http://www.documentfoundation.org/download/and set LMDE to use Libre Office Impress as default to open .pps
Now I got the background sound reproduced normally !
I'll keep Open Office installed for a while but since have not encountered any
kind of problem so far using Libre Office, I will disinstall Open Office very soon.
The Libre Office suite is complete like Open Office and from what I saw in the
web it will be the default Office suite in the next release of Ubuntu 11.04.

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