[OMP 3.1.2-4] Custom report generator output is empty

Hi,

we are testing the statistics part of OMP.
Using the custom report generator (click on Generate custom report in Statistics>Report generator) we always obtain a csv with no data after column name, despite the options we set.
If we click on “PKP Usage statistics report” link we obtain a csv with data.
Can anyone help?
Best regards,
Stefano