Installed the coverage plugin into Flash Builder 4.5 and it appears to be working correctly. It says I'm connected to an application when I run it and when I press stop the report button becomes enabled.
The problem is that when I click on the report window... the report button is completely empty even when I remove all of the filters.
Did you ever resolve this? I'm experiencing the same issue. When I save a report, the associated ascs file is empty. This file is supposed to contain your source code, so I suspect this issue is related to the plugin not being able to see your source code.
I'm having a similar issue - for me, the report is generated but there are no packages in it. How can I find out what is wrong?