Updates from Nick.

src/osgPlugins/txp/TXPArchive.cpp

@@ -557,7 +557,7 @@ osg::Group* TXPArchive::getTileContent(int x, int y, int lod)
     trpgMemReadBuffer buf(GetEndian());
     if (!ReadTile(x,y,lod,buf))
     {
-        return NULL;
+		return new osg::Group;
     }
 
     osg::Group *tileGroup = _parser->parseScene(buf,_gstates,_models);

src/osgPlugins/txp/TXPNode.cpp

@@ -103,6 +103,7 @@ bool TXPNode::loadArchive()
         return false;
     }
 
+	/*
     if (_archive->loadMaterials() == false)
     {
         TXPNodeERROR("loadArchive()") << "failed to load materials from archive: \"" << _archiveName << "\"" << std::endl;
@@ -120,6 +121,7 @@ bool TXPNode::loadArchive()
         TXPNodeERROR("loadArchive()") << "failed to load light attributes from archive: \"" << _archiveName << "\"" << std::endl;
         return false;
     }
+	*/
 
     _archive->getOrigin(_originX,_originY);
     _archive->getExtents(_extents);