Ruby FTP broken in Panther?

On panther, Ruby 1.8.0 and 1.6.8, this fails for me. (ftp connection
opens ok)
ftp.puttextfile(“testfile.htm”, “testfile.htm”),

/usr/local/lib/ruby/1.8/net/ftp.rb:276:in addr': getnameinfo: nodename nor servname provided, or not known (SocketError) from /usr/local/lib/ruby/1.8/net/ftp.rb:276:inmakeport’
from /usr/local/lib/ruby/1.8/net/ftp.rb:310:in transfercmd' from /usr/local/lib/ruby/1.8/net/ftp.rb:451:instorlines’
from /usr/local/lib/ruby/1.8/net/ftp.rb:449:in synchronize' from /usr/local/lib/ruby/1.8/net/ftp.rb:463:instorlines’
from /usr/local/lib/ruby/1.8/net/ftp.rb:554:in `puttextfile’

Same code works o.k. on Windows. Any ideas what to try next?

George Girton