Patch by Alex Sisson (alex_sisson at yahoo.co.uk):
a missing parameter on mp_msg meant it crashed instead
of printing a nice message if you put entries in the
config with no parameter.
also did a few english-tidies on error messages in
there.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@10246 b3059339-0415-0410-9bf9-f77b7e298cf2