Compiling examples

Hi,

Instead of asking newbie questions here (which are not answered anyway
;-), I decided to take it the long way and compile all examples to see
whether they cover what I'm looking for...

However, I ran into trouble as early as the second (in lexicographic
order) file, namely "accel_tree.ml"!

First, it lacks a comment in the header giving the full command line
to compile it.
So I thought I'd try the same command as for "about.ml":
* ocamlc -g -I ../src lablgtk.cma accel_tree.ml -o accel_tree
Which gave me the (not so unusual) warning:
* File "accel_tree.ml", line 80, characters 2-32:
* Warning S: this expression should have type unit.

Executing it terminates immediately with the cryptic message:
* Fatal error: unknown C primitive `ml_gtk_tree_view_get_visible_range'

Googling this primitive produced only one page:
http://old.nabble.com/Patch-to-add-binding-for-gtk_tree_view_get_visible_range-td26901400.html
which didn't enlighten me much, even more so given that this message
dates from December 2009, whereas file "accel_tree.ml" dates from
August 2008...

Any hint on how to solve this?

Thanks in advance.

--Serge