Tnx 4 response
I think that I am in error with the procedure to upgrade to 2.0 from 1.7 !
I have the working vers in /var/www/tracks
I have downloaded the 2.0 zip vers, and I have unzipped in another folder named tracks20
I have copied the config file in the new installazion (cp /var/www/tracks/config/* /var/www/tracks20/config/)
then I have launched the db upgrade
rake db:migrate etc etc
Now I get the error !