Problem installing lilypond 2.6.1

[Luis G . López]

Hi!

I had installed 2.4.2 some time ago; it was very hard for me (and for
you, as you had to help me through the list :-)).
Now, I downloaded the .package file of 2.6.1. Everything went fine,
but when I want to run lilypond, I get the following message:
-------------------------------
/usr/bin/lilypond-bin-2.6.1: /usr/lib/libstdc++.so.6: version
`GLIBCXX_3.4.4' not found (required by /usr/bin/lilypond-bin-2.6.1)
------------------------------

Please, can you tell me what I am doing wrong? Thank you!!!!

Luis.