Rational Insight - Drill down from active report to xlsx report does not work

Hi,

A wired problem I have, hope to get some help...

We use Rational Insight, and have both "active reports" and "regular" reports.
I'm using Firefox with UnMHT to view the active reports.
I can run an active report and get the mht file and open it (with Firefox).
In the report we have drill-through to other reports.
If I drill-through to another active report - everything works fine, and the report runs and can be viewed.

However, when I try to drill down to a regular report, with default output as xlsx - it looks as the report is running, and then I get an empty screen. No report to download/save.

Other people in the project, using the same reports, and same Firefox version do not see this problem.

Thanks ahead for your help,
Raviv.