Can't secure connection between access point and wireless card

Hello:

Although I am able to connect wirelessly to the net via an unsecure
connection I am not able to secure the wireless portion of my network with
WEP...haven't even gotten to the point to try WPA.

My set up is as follows..
1. Mixed wired and wireless LAN
2. Router is a wired Linksys Cable Router BEFSR41 V2
3. Wireless Access Point is a Netgear WG602
4. Wireless Ethernet card is a D-link DWL-G520

Unsecured access is not problem...it's when I try to secure the Wireless
Access Point with WEP, I can no longer make the wireless network connection
work.

Any suggestions on how to fix or a step-by-step guide in configuring a mixed
wired/wireless LAN with wireless security enabled?