sitecom wireless network no internet

Hi!
I just bought a sitecom WL-108 router and WL-112 accesspoint for my
laptop (windows XP SP 2).
after installing the router it said in the testwindow: internet OK.
When I connect my laptop via an ethernet cable to the router I get
Internet connection. but via wireless connection I dont. However via
wireless connection i can see the router (http://192.168.0.1) and even
configure it.
my desktop has the same problem (windows 2000).
can anybody give me some advise on what I have to do to get an
internet connection wireless?
thanks in advance!
Paul.