Before reporting a bug in bash-completion, please check that you don't have
Acrobat's acroread.sh installed in /etc/bash_completion.d/. That completion,
in fact, redefines internal bash-completion functions, breaking it.

For more information about this issue, please read:

  - http://forums.adobe.com/thread/745833
  - http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=616018