Have you got other wireless connections, and do they work fine? Is the SSID visible over wireless on another client? Have you enabled wireless-G on the router (the DCS-5300G is a wireless-G-only device)?
When wired you could connect and use the camera?
Are you using the same 'family' of IP-addresses (so, for example, 192.168.0.x) for all clients?
Have you set the ip-address of the camera to a fixed address, or retrieve from DHCP out of the router?
If you look at the status-screens of the router, can you see the camera (if DHCP-allocated address) in the list of clients, or can you see the (fixed) ip-address in the list of active sessions?
These are just a few questions to follow when attempting to troubleshoot connectivity-issues...