Replying to Help with Custom Grabs

ok i have been having problems importing my custom .kmz files

1. i have Sketch Up 6

2. i export 3D models "Google Earth 4" .kmz

but whenever i save them in the models folder and open the html file when i press the grab button my model disappears

1. i reDownloaded the files using Firefox but it still doesnt work???

any help would be great

thanks