Kasper, are you the administrator of this network or just someone trying to use it? If someone else operates the network, you will need to speak with them first. For example, they may not be allowing 802.11B devices on the network (which PS3 requires), or there may be device or MAC access controls in place.
http://faq.en.playstation.com/app/ans... has some basic steps to try, but if you don't have access or understanding of how the ruckus equipment is configured we won't be able to help much.