You write that you are using "WPA-PSK with EAS encryption (WPA2)."
Although WPA-PSK with AES encryption uses the encryption algorithm
specified for WPA2, it does not have all of the security features of
WPA2. There is no reason I know of why WPA-PSK (AES) should be looking
for a certificate (certificates should only be required when using
WPA-Enterprise), however, if you do not have an option in Wireless Zero
Configuration for WPA2, you should download and install
Wireless Client Update for Windows XP with Service Pack 2
Alternatively, use the configuration utility for your wireless adapter.
Be sure to disable WZC if you do this. There may be an option in the
mfr's utility that will do this for you, or you will have to do it
manually, such as described at http://www.ezlan.net/wzc.html
In addition, both ends of your wireless connection -- router and adapter
-- need to have the same security configuration. In addition to making
sure that your adapter is set to use WPA-PSK (AES) (or WPA2-PSK), you
also need to make sure that your DIR-655 is not configured to use
WPA2-Enterprise. Double check this in the configuration utility of your
Lem MS MVP -- Networking
To the moon and back with 64 Kbits of RAM and 512 Kbits of ROM.