CD5ENGINE API Does not work.

I want to load a part from 3dexperience to catia v5 session . so that 3dxml file is generated in 3dexperience v5 cache folder(i want to generate 3dxml file ). Catia is integrated with 3dexperience . I have checked some of API'S , I got CD5Engine , which fails in retrievin gin getitem method. It shows "GetItem method failed error"
Please Suggest .