Let me type the question again, because I was not very clear first time.
I use a Netgear Hub, which works absolutely fine when connected directly to the mains. But when I connect the Hub to a UPS (APC Smart UPS 450) it lights up as normal but none of the connections to the hub work. If I connect the hub back to the mains it will work straight away.
Iím not changing anything else apart from the power source (either UPS or direct to the mains). The UPS works fine in every other application I have tried it i.e. server or printer etc.
It cannot be too much load on the UPS, as none of the warning lights are lit up on the front of the UPS. Itís not imperative that I get this working, itís just irritating me, because it should work!