"message": "Uninitialized string offset: 0"

Have you tried this?

PHP Code:

$pQuery->execute("slug","url","title","abstract","authors","areas",
"keywords","journalName","volume","issue","pageNumber","indexing",
"publishDate","creatingAuthor","ip","pdfTitle","pdfFileName",null, null); 


Yes Null also no error its working fine only problem with empty string.

if I entered any field empty then error i tried named prepared statement also giving same error.

Is my prepared statement is correct?