"no results were found" in a BIRT Report on Dashboard

On my RTC 4.0.1 I've created a BIRT report and I can run it without problems from "Report" menu choice.

I've create a micro report (starting from my report) following the instructions of this links
https://jazz.net/wiki/bin/view/Main/HowToCreateMicroBIRTReportTemplates 
and I've added the micro report to the available widgets following this instructions
https://jazz.net/wiki/bin/view/Main/HowToAddNewDashboardTrendReports#Run_time_process_contribution_me

I can configure the report, the preview is correct but unfortunately, when I click OK, on widget there is only the message
No results were found
 
Same behaviour with "Report" widget.

Please, can you help me?
Thanks in advance.