are you doing an autodetect of the available wireless networks? i would recommend this so that the WPA2 settings are correct. the 3600 handles multiple types of wireless security models WEP, WPA2-PSK/TKP, AES -- at least it seems that it's AES (though, I haven't ever got this to work well). So autodetecting it would be best since the player will notice the type of security to handshake with. but if you are sure of your settings and all else is failing, i'd go manual to drive it home (i believe the manual says this as well in nicer words).
Then there is the issue of passphrase/shared security key. Not sure about the netgear, but sometimes, wireless routers don't like set-top devices' (ie Wii, Xbox, Bluray players) input methods and you end up putting in the hex. haven't had to do that for devices since my last router a long time back, so i'm hopeful that it isn't the case for you. And personally, I haven't had to do that with my dlink 4500 (wireless N), so I doubt that's the case.
now here are some steps i want to point out to you and others in case it was missed. when typing out your passphrase/security key after an autodetect, make sure you press the right button (possibly more than once) after you've finished inputing your passphrase/key so that it goes back to highlighting the password (i think that was the name) option. ie, press the right key after your password until you can see your passphrase correctly displayed but your highlight has gone back to the menu instead of a cursor on your passphrase input line. once there, your phrase is now stored "in the system" and you can test your network connection.
...and of course...you plugged in the wireless dongle, right?