After a failed install in GnoRPM, it always brings the main window back to the front, occluding any Install windows that might have been open. The problem is worse if GnoRPM is run maximized. In any case, I don't think this is correct behavior, since the user might have clicked "Install" instead of "Upgrade" and now has to find the other window again to try the other option.
In order to get the developers and maintainers of GnoRPM to look at this bug I have moved it to the GnoRPM category in the Gnome bug tracker. It can be found at http://bugzilla.gnome.org/show_bug.cgi?id=58460, where you can add yourself to the cc-field if you want to recieve information about changes to the bug tatus.