query error

[eluser]basty_dread[/eluser]
i use this query

Code:

function checkifkewordlist(&$islist,$keyno){
            $this->internalvalidate();
            $query = $this->db->query("select iKeywordList from tblkeywords where iKeywordNo = ".$keyno);
            $row = $query->row();
            $islist = $row->iKeywordList;
        }

this is the error:

Code:

Severity: Notice
Message: Trying to get property of non-object

how this become an error?

what could possibly wrong?