"getaddrinfo: Name or service not known" error. MySQL driver?

Dear list:

I have one app running merrily on a Linux box. I can run "rake
migrate" on it with no trouble, start it, stop it, and restart it.

I created a second app and uploaded it to the same box. Aside from the
database names, the database.yml files are *exactly the same*.

Yet when I run "rake migrate" on the new app, I get: