Ok, I started from the beginning updating my real forum: phpBBXS 0.58b
What I did till now.
1. Backup database.
2. Backup files.
3. Created subdomain and database for tests.
4. Imported files and database.
5. Modified config.php and config table in order to make the forum work on the test subdomain.
6. Check if the clone forum is correctly running: OK.
Then, I proceed to the upgrade:
7. Uploaded update_to_ip.php to my root
8. Logged in as admin.
9. Launched update_to_ip.php and chose "Upgrade from phpBBXS 2 0.58"
10. Upgrade done, no errors except for a duplicate entry for the xs version, nothing important I think.
11. Moved album files.
12. Deleted folders and files as suggested by MG.
13. Uploaded new files.
14. Uploaded backup of config.php and def_*
15. CHMODs checked.
Try to access site and ERROR: ca_aphrodite not found.
16. Uploaded ca_aphrodite folder.
Template->make_filename(): Error - template file not found: portal_page_headerleft.tpl
I'm stuck here