Hello,
The "Access denied" error would be caused becuase the "da_admin" user isn't setup in mysql. It needs to be setup to have full root privileges. Normally this is done during the install, but if mysql already existed, and you chose to not overwrite it during the install, then the user won't be added.
The 2nd error: That database is not yours
means that the naming convention fo the database is off. The database name needs to match up with the username: username_db. For the next release of DA, the database restores will automaticaly adapt to a different username. (backup/restore feature).
John