An outdated or corrupt RocketLauncher module can also cause this break in communication. Within RocketLauncherUI, go to the specific system and check the Modules tab. Ensure the module for your emulator (like RetroArch or MAME) is up to date and pointing to the correct emulator executable.
Sometimes, Windows security prevents Hyperspin from calling an external program. Try running both Hyperspin.exe and RocketLauncher.exe as an Administrator. You can set this permanently by right-clicking the .exe files, selecting Properties, and checking Run this program as an administrator under the Compatibility tab. Update Your Modules hyperspin cannot find launcher top