Nodes Incompatible

Hi All

as suggested in this thread Passing a Context Node to a BAPI

I am using wdCopyservice to copy my context Nodes to my model. Unfortunateley i get an error, saying my nodes are not compatible, although they are from the same modeltype. Can anyone help?

Z_Kp_Paf_Write_Input si = new Z_Kp_Paf_Write_Input();
	wdContext.nodeZ_Kp_Paf_Write_Input().bind(si);
		//Node Depprojects
	try
	{
		Zkps_Depprojects dp = new Zkps_Depprojects();
		int size = wdContext.nodeDepprojectsView().size();
		for(int i=0;i<size;i++)
		{
			WDCopyService.copyCorresponding(wdContext.nodeDepprojectsView().getElementAt(i),dp);
			si.addDepproject(dp); 
		}
		wdContext.nodeDepproject().bind(dp);
	}
	catch(Exception e)
	{}