Regarding the path to the H910, make sure that you have the correct 32-bit/64-bit path specified for the version of Reaper you are using (32/64-bit). You could also try a "rescan" of the plug-ins. Of course, it's also fine to put the H910 in the Reaper plug-in folder if you like, providing it's the correct 32 or 64-bit version.
Could you give me a bit more info into exactly how Komplete crashes? Does this happen when you try and instantiate the H910, or simply if the H910 is in the plug-in folder at all? Does an error message pop up when it crashes? If so, could you post it here? If you open H910, and then Komplete, does Komplete load then?