It sounds as though the device is operating off a different set of maps to us, but you really need to contact Bosch about this, as we have no way of knowing why they are generating the error message.
I'm having a problem importing a saved GPX file to my Nyon navigation device. Some files are all fine and complete. Others have an error attached " Could not map your route to existing roads. Your route will be visible on Nyon without turn by turn directions."
Can anyone please help? It's driving me nuts!!