Sorry to hear about your troubles. I can try to help walk you through the setup, even though I am not familiar with that product...
First off... I will start by saying that no, I don't work for D-Link, but I suppose you could say I am a D-Link Fanboi.... my network is all D-Link, and I love it.
Secondly, PERSONALLY, I stay away from the "Wireless Draft N" standard like the plague.... it has yet to be fully ratified, and is still in the 'Draft' stages. You really have to read the fine print, and be up on your game with this.... PERSONALLY, I have to say
SHAME ON D-LINK, and SHAME on all the other OEM hardware companies that are jumping on this "Pre N" or "Draft N" bandwagon... It's totally RUBBISH. Basically, consumers are purchasing BETA DEVICES. That being said (sorry, lol), here is what the DAP-1522 page shows....
Bottom of the page.....
http://www.dlink.com/products/resource.asp?pid=663&rid=2650&sec=0
This product is based on IEEE draft 2.0 802.11n specifications and is not guaranteed to be forward compatible with future versions of IEEE 802.11n specifications. Compatibility with draft 802.11n devices from other manufacturers that are not Wi-Fi® certified is not guaranteed. All references to speed and range are for comparison purposes only. Product specifications, size, and shape are subject to change without notice, and actual product appearance may differ from that depicted herein.
Third thing.... Seeing as this device is still in its firmware 1.00 revision, which was released 04/08/2008, this thing is still VERY much in its infancy, and bugs are to be expected.... That goes hand in hand with purchasing a newly released piece of hardware... You just have to either work with it and accept the rough road in the beginning, or choose a more mature platform. I have been there myself with my D-Link DNS-323, which I bought days after its release, but I LOVE the thing, even with my new recent issue, which I already resolved....
Anyways... on to helping you out with this.
Connect a PC directly to the unit, and give the PC a STATIC IP address of
192.168.0.x (pick a number between 1 and 254, EXCLUDING 50) with a subnet mask of 255.255.255.0
Once that is done, open your web browser and type in 192.168.0.50. This should bring you to the configuration page for the DAP...
The router and the DAP will have to be in the same subnet in order to work... By default, the DGL-4500 is 192.168.0.1 and the DAP-1522 is 192.168.0.50 both with 255.255.255.0 subnet masks.. This shouldn't be a problem. I would recommend that you DISABLE DHCP in the DAP, and let the DGL handle the DHCP requests... you don't want to have 2 DHCP servers in the same network... makes things hairy.
As far as security goes, I would HIGHLY SUGGEST that you add some for of actual security to the wireless, other than just having the SSID being 'hidden' (which for the record really doesn't do anything... people can still connect to it)... Personally, I use a WPA2 scheme with a 63 character ASCII key, in addition to MAC filtering, and hidden SSID....
Since I haven't worked with bridged wireless connections before, I can't say with 100% certainty, but I THINK That the SSID's for both the DGL and DAP have to be identicle.... but again, I can't confirm that, because the 'stuff' hit the fan at work, and it is really busy right now.... let me know how far you get....