Waves plugs show an empty grey window, desperate

[andre tchmil]

I have the Platinum full version on my G5 , running without any problem.
But now I installed the demo versions of GTR and Vocal bundle.
Installation went fine, the plug show up in my plugin list, but when I insert one of these, all I see is an empty window, although I can hear the plugin working

I contacted Waves support, but no rersponse back from the , aaarrrgghh.
By the way , all my other plugins from different brands (including the Platinum ones !!! )are working fine.