CWM Tether.app vs OpenVPN on Mac OS X / macOS
Error description
An "Error loading /tmp/tun.kext" in Clockworkmod's Tether.app for the Mac typically (often?) means that Tether.app failed to detect and unload an interfering tun/tap kext.
Tether.app thus gets an error return from the OS when it tries to insert itself into an already occupied spot.