Just a quick thought...
Have you set your router's DHCP to give each OBi device a Static address?
I've had issues in the past just getting my OBi100 and my OBiAPP to work. I followed RonR's posts, and it had no effect. But, after giving the OBi100 and my PC, each their own Static IP address through the router, it solved my issues.
On the Network Settings of the OBi100, I left it as DHCP (defult).
Depending on your router, it should then handle the port needed for each device on it's own.
However, setting one device to use say 5060 and the other to use 5075 or something, should help too.
Good Luck with it, and report your results.
-G