On Tuesday, 10 Jan 2017 at 12:26, Nicolas Goaziou wrote:

[...]

> Could you provide an ECM?

Yes, of course:

#+begin_src org
  ,* Simple illustration of nil link error message
  In table [[mytable]], there are some numbers
  ,** the table                                                 :noexport:
  ,#+name: mytable
  | x | y |
  |---+---|
  | 1 | 1 |
  | 2 | 4 |
  ,#+TBLFM: $2=$1^2
#+end_src

There is a reference to a table which is in a subtree that is not to be
exported.  The error message is

   user-error: Unable to resolve link: nil

This ECM may appear contrived but, when working with a large document,
it is easy to comment out or exclude sections that, it turns out, have
material within that is referenced from elsewhere.  This is difficult to
track down when exporting.  If the error message had "nil" above
replaced by "mytable", it would make all the difference!

Many thanks,
eric

-- 
: Eric S Fraga (0xFFFCF67D), Emacs 26.0.50.1, Org release_9.0.2-104-gf5b7de