5.1 is a ways off unfortunately, I'm aiming for an April-May release though I may be able to do a minor bug-fix release earlier. Since I am a full-time student, I don't have large amounts of time during the Spring and Fall to work on the module (though I may put out a call for some team members soon). As a temporary workaround, if you don't need Search Indexing on the Reports Module itself, you should be able to stop that from happening by changing the SupportedFeatures column in the DesktopModules table (see this thread for details). This SHOULD stop the Search Indexer from indexing the Reports Module, thus avoiding the exception and allowing the other modules to be indexed properly.
If you need the Reports Module indexing features, I'll have to fix that bug to give you a workaround, but I should be able to do that relatively quickly and provide you with a quick patch if you need it urgently.