[Koha-devel] Error exporting report!

hi, I'm trying to export a report from the page "reports/guided_reports.pl" in interanet. When I create a report it works fine and shows result. But when I click on "Download" button to export the report in any format(CSV/Tab Spaced), it doesn't work. It just shows an error: "Error exporting report!". I've tried it on two different machines having different installations, but both don't work. Please help ! Regards, Muhammad Wasim