Mail Statistic problem

Hi all.Recently our customer have a strange problem with the statistic of mails.

In the statrep.nsf I can see all statistic (task, probes, etc) but when I select the statistic of mails, I can see only a N/A on every field (=no data).

Anyone knows why :(?

I have try to replace the design of database, re-create the views but the problem still exist.

Thank you in advance!