Router and AP configuration

I have the following:

Netgear FWAG114 Firewall Router (channel 6)

Netgear WG302 Access Point (channel 6)

I have the Router configured with WPA-PSK and the Access Point configured as
a Repeater.

I have entered the MAC addresses in both systems of all the wireless nodes.

The problem is that I can not configure the Access Point with WPA-PSK. I
select the appropriate options, enter the Passphrase and select Apply but it
reverts back to OPEN. Does this mean that it is not required by the Access
Point since it is configured as a Repeater only?

Everything seems to work but is it secure?

I's appreciate any feedback I can get.

Thank you.

Simon