Hi,
I often see people who have installed the "StoreOnce Software Deduplication" component on a gateway system. This is not needed. This component contains the StoreOnce server software which is needed to setup a Data Protector StoreOnce server (the software version, as opposed to a StoreOnce hardware device). For a gateway, the needed StoreOnce Catalyst API is already embedded in the Media Agent component. So, installing the Media Agent is enough to have a gateway to a StoreOnce server (hardware or software).
Koen