[TYPO3-dam] unable to use previously saved dam selections after moving to a new server

[Mathieu Kessler]

Dear list,
I want to move a working typo3 website with Dam to a new server. I
made the sql dumps etc...imported the database etc... and everything
works fine on the new server, exept for the dam selections.:-(
The selections that I had defined in my old server don't work in the new....
I have checked the database and could see that in the table
tx_dam_selection, the definition field contained the absolute path to
the directory on the old server, e.g
a:1:{s:6:"SELECT";a:1:{s:11:"txdamFolder";a:1:{s:88:"/home/sandieg4/public_html/sandiegotypo3/fileadmin/imagenes/viernes/temporada2008/02_05/";s:1:"1";}}}
I therefore thought that I had found the problem since the typo3
installation is not in the same folder in the new server as in the old
one.
I then changed with sed all the ocurrences of
"/home/sandieg4/public_html" to the new base path:
"/var/www-data/apache2-default/" in the sql dumps files
and reconstructed again the database. The path that appears in the
definition field of table tx_dam_selection is now correct, but the
selections still don't work!
What is even more puzzling is that I can define a new selection in the
new server selecting the same directory and this one works!
If I compare the selections rule of the old selection (that does not
work) and the new selection (that works) they are almost the same:
old selection:
a:1:{s:6:"SELECT";a:1:{s:11:"txdamFolder";a:1:{s:88:"/var/www/apache2-default/sandiegotypo3/fileadmin/imagenes/viernes/temporada2008/02_05/";s:1:"1";}}}
new selection
a:1:{s:6:"SELECT";a:1:{s:11:"txdamFolder";a:1:{s:86:"/var/www/apache2-default/sandiegotypo3/fileadmin/imagenes/viernes/temporada2008/02_05/";s:1:"1";}}}
What am I missing?
It seems to me an  important issue when making backup copies of an
existing typo3 site with many dam selections...
Many thanks in advance for any hint...
-- 
Mathieu