There is a possibility that the file to be deleted does not actually exist, so can I do a test first so that i only delete if it is present and thus avoid any nasty warning about missing files?


The Chilkat components/libraries never pop up warnings or display error messages — they simply return success/failure status and provide error information that your application may choose to display.    I would only check to see if the file exists if the delete failed.  It’s more efficient, and you can ignore errors caused by missing files.