The .IVE files on the TrianGraphics.de website use a later version of OpenSceneGraph than the version Vizard is based on so the .iVE files will not load directly into Vizard. I see that some of the samples are available as OpenFlight. If you have 3DS Max, its newer releases include OpenFlight import functionality. You might try importing as OpenFlight into 3DS Max, and then export as the Vizard compatible OSG/IVE format (which you can download here:
http://www.worldviz.com/download/fil...9.4Install.exe).