Have you also downloaded the update patch? Sometimes it's necessary to both download the client and the update patch to get it working.
You can this link to download the client:
http://wl.igg.com/download/downCnt.php?did=40
Or this one:
http://us-ca-d1.iggcn.com/wl/20091124/wl_setup_...
If you want to download the update patch, go here:
http://us-ca-d1.iggcn.com/wl/20091125/wl_up_5.0...
What's exactly the problem you're having?
Good luck!