From the looks of it everything on their network may be down. My traceroute to NS2.POWWEB.COM took a whack C shaped route all around the continent before getting to them and then times out. If their nameservers are offline try accessing your site via its IP address, if that doesn't work they're likely having problems with their upstream provider.
It's the only one of my sites that I don't have hosted through my Reseller account at Splashhost. I may just go ahead and move it over to Splashhost anyway. I have lots of room there.
I can't get any credit from Powweb as I'm paid up on this account through November.