Ulf Stegemann <ulf-news@zeitform.de> writes:

Hi Ulf,

> After a bit of investigation I found out that the problem is
> `gnus-group-read-group' which is called by `org-gnus-follow-link'.
> `gnus-group-read-group' does not return an article but nil if the last
> message of the group has been deleted (this is re-producable here).

Not really.  But it won't open the Summary buffer if the last article
was deleted.

Please try this patch and report back if it works.