Sees network, won't connect

I have a Sony SMP-N-100 streaming media player I am trying to connect to a 2WIRE 1800hg router. The player sees the router/network. When I go through the setup and type in the WAP it will not connect. I can disable the security on the router and it will connect just fine. I have messed with this for the last 2 days and cannot get it to connect through the WAP. Have checked, changed, and double checked the WAP key. All my other wireless devices work fine. What could be the problem????

try changing the security mode on the router to WPA TKIP