If you have more than one router, until you set up port forwarding, your computer and the camera must both be connected to the same one (wired or wireless it does not matter).
If you are connected through the same router, try to simplify things as much as possible until you identify the problem:
When you pressed the scan button, was your router shown and could you select it? If it is not shown, try setting your router to broadcast the SSID. Then you should be able to select it in the camera's setup.
If you are using WEP or WPA security, temporarily setup your router without security and try to connect to it again with the camera.
Let me know if you are still having problems.