Today I had the ISP go to the site and replace the cable modem. Recap of problem:
Arubal 7005 controller running ver 6.4.3.9 connected to cable internet service from Cox Communications (cable modem was a Cisco DPC3021).
Nothing seemed to work when connecting the controller to the cable modem, after much troubleshooting as best as I can tell, it appears to be a hardware compatibility issue between the Cisco DPC 3021 and the Aruba 7005. Whenever the ISP (Cox Business) replaced the Cisco cable modem with a Motorola/Arris Surfboard 6183 it immediately came up and started working. Prior to that, the only way I could get it to work was to put a small switch (i.e. Linksys or something) between the two devices.
I have the exact same problem at another site (also exact same hardware involved); I have the vendor scheduled to replace the cable modem there also. I feel relatively certain this will fix the problem there also.