Problem with statistics-interval

[Eric Allard]

We use bind 8.2.6 REL on Solaris 8 and have a problem
with the statistics-interval. I configured a statistics
interval of 15 minutes and didn't get anythings.
When I use "ndc stats", I get statistics. I would like to
obtain my stats automatically every 15 minutes!

What should be the problem?
How can I solve it?

Here one part of my options in my named.conf:

statistics-file "/tmp/named.stats";
statistics-interval 15;

Thanks!