A ".sldprt.cvd" file is a Virtual SolidWorks Part document
There is no data in the file which will be why you cannot open it. It will have been created inside Enterprise PDM as a placeholder until someone had time to create the real file.
If you need to add SolidWorks data to this file then you can Right Click on it and select Replace. This then allows you to find a SolidWorks Part to replace the virtual document with.