Hi Sven,

On 26 May 2011, Sven Bretfeld wrote:
> Michael Markert <markert.michael@googlemail.com> writes:
>
>> Hi Sven, I run org-contacts on Emacs 23.3, there is a
>> `completion-at-point-functions' and org-contacts works just fine.
>> But I recall myself trying with Gnus and it didn't work because
>> `completion-at-point' was not bound to keys.
>
> It is definitely not there in 23.1, the emacs-snapshot package which
> AFAIK is the orebokech version that seems not to have been updated
> since quite a while. I have checked the sources of minibuffer.el and
> it does not define completion-at-point-functions.

Oh I didn't say that, just, that it happened before Emacs 24.

Digging furher, you need (at least) Emacs 23.2:

,---- Emacs Changelog
| * Editing Changes in Emacs 23.2
|
| <snip>
|
| ** Completion changes
|
| *** The new command `completion-at-point' provides mode-sensitive completion.
`----

So you could try the Emacs 23.2/23.3 `minibuffer.el' compared to a Emacs
24 version it should be more suitable.

Good Luck,

Michael