This is the local IP setting of the gateway. It expects to be connected to a router with 10.0.0.1/8 witch will NAT to the Internet. In other words, the D-STAR device has a default route via 10.0.0.1, that's all. No conflicts here.
Well, I agree with Pedja that it is an extremely unfortunate choice and that it would have been much more convenient when it supported 44-net addresses or even an arbitrary address on the LAN.
We are running several D-Star repeaters and this requirement makes it very difficult to share resources. Even running multiple D-Star gateways on the same ESX system is more difficult than it ought to be (when a single router is running in another VM).
Also note that this program has other strange requirements. It requires an ancient CentOS distribution, for example. That is why we want to put it in some ESX VMs.
Rob