Comment 17 for bug 514989

For anyone else who's hit this, the page has now moved to http://www.clock.co.uk/blog/bash-completion-problems-with-option-lists-generated-by-php it's also still available in Google's cache here:
http://webcache.googleusercontent.com/search?q=cache:n-AfIM1nmMYJ:http://clock.co.uk/blog/bash-completion-problems-with-option-lists-generated-by-php%2Bbash+completion+problems+with+option+lists+generated+by+php&rls=com.microsoft:en-gb:IE-SearchBox&oe=&gfe_rd=cr&gws_rd=cr&hl=en&ct=clnk

And the key info (in case it vanishes again) is:
  targets=`echo ""| maiden -b | sort -u`
  COMPREPLY=( $(compgen -W "${targets}" -- ${cur}) )
  return 0

i.e. add echo "" | before your PHP script.