Nice example for young modders.UV errors are all right and than this:
"If you can not handle dds, you can save the file as png. In that case you have to open the file “sign.i3d” with the editor and change the line
“<File fileId="7" filename="textures/aufdruck.dds" relativePath="true"/>” in
„<File fileId="7" filename="textures/aufdruck.png" relativePath="true"/>“ first of all it does not mater if you have dds or png in editor and when you not gonna save texture as dds format you gonna get Raw texture error message and it does NOT need to be DTX5.DTX1/1bit alpha for opaque textures and DTX3/explicit alpha for transparent or semitransparent. Hope that will learn somebody something...