From Simon Buckley, "Attached is a small change to the file src\osgPlugins\dxf\dxfFile.cpp that allows the dxf reader to skip comments in a dxf file. I found with the existing version and a test file I had that the loader failed when comments were present. I made a very minor change to allow "999" comment codes to be skipped rather than causing load failure."

src/osgPlugins/dxf/dxfFile.cpp

@@ -91,6 +91,7 @@ dxfFile::assign(codeValue& cv)
         _isNewSection = true;
     } else if (cv._groupCode == 0 && s == std::string("EOF")) {
         return 0;
+    } else if (cv._groupCode == 999) {    // skip comments
     } else if (cv._groupCode == 2 && _isNewSection) {
         _isNewSection = false;
 //        std::cout << "Reading section " << s << std::endl;