Do you get any errors in the console or firebug? We have several applications with reports running in 2.5, so there should be no problem there..
The reporting library should be in (mendix installation dir)\runtime\mxclientsystem\reporting, which contains the directories FusionChartsFree, lib, mixin, store, ui and widget. The first one contains swf files (in the subdirectory charts).
Is the case that the reports won't show on the production deployment, or that they do not work at all?
Issue resolved, the generated key did not have the FucionCharts incorporated.
if only all problems where as easily solved 8-)