From Per Fahlberg, "I've fixed the dae plugin so it is only using one instance of the DAE.

The crashes seen earlier are gone, it is now possible to read multiple
.dae files and converting both to and from .dae files."

src/osgPlugins/dae/ReaderWriterDAE.cpp

@@ -29,8 +29,20 @@
 class ReaderWriterDAE : public osgDB::ReaderWriter
 {
 public:
-    ReaderWriterDAE() {}
-    
+    ReaderWriterDAE()
+    {
+        dae_ = new DAE();
+    }
+
+    ~ReaderWriterDAE()
+    {
+        if(dae_ != NULL){
+            delete dae_;
+            DAE::cleanup();
+            dae_ = NULL;
+        }
+    }
+
     const char* className() const { return "COLLADA 1.4.x DAE reader/writer"; }
 
     bool acceptsExtension(const std::string& extension) const
@@ -41,6 +53,11 @@ public:
     ReadResult readNode(const std::string&, const Options*) const;
 
     WriteResult writeNode(const osg::Node&, const std::string&, const Options*) const;
+  
+private:
+
+    DAE *dae_;
+  
 };
 
 ///////////////////////////////////////////////////////////////////////////
@@ -57,7 +74,7 @@ ReaderWriterDAE::readNode(const std::string& fname,
 
     osg::notify(osg::INFO) << "ReaderWriterDAE( \"" << fileName << "\" )" << std::endl;
 
-    osgdae::daeReader daeReader;
+    osgdae::daeReader daeReader(dae_);
     std::string fileURI( osgDB::convertFileNameToUnixStyle(fileName) );
     if ( ! daeReader.convert( fileURI ) )
     {
@@ -100,7 +117,7 @@ ReaderWriterDAE::writeNode( const osg::Node& node,
       }
     }
     
-    osgdae::daeWriter daeWriter( fname, usePolygon );
+    osgdae::daeWriter daeWriter(dae_, fname, usePolygon );
     daeWriter.setRootNode( node );
     const_cast<osg::Node*>(&node)->accept( daeWriter );