Currently there is no option to disable DHCP on the private LAN of the NetBotz 750. Without it, there is no way to automatically add APC devices such as cameras. This network should never be connected to your normal network so DHCP should only interact with those private LAN devices and not effect your normal networks.
Sorry but again, no. The only options are the ones we provide (or don't provide) in the web client. Making any changes through the Linux interface it unsupported and any changes could cause adverse effects to the operation of the system.