Some Kenwood dealers will allow a one-time programming session if you bring the radio to their shop. They might charge $25-$50 to write your codeplug. Not "software download," but you get the job done.
Go to Kenwood.com → "Where to Buy" → Select your country. In the US, dealers include: kenwood kpgd6n software download free
Connect your NX-5000 radio via a KPG-46U programming cable (USB). Power the radio on. KPG-D6N should auto-detect the radio. Read the current codeplug (Model → Read) before making any changes. Some Kenwood dealers will allow a one-time programming