The original recordset that Ray created was for use with the Power CMS Contents table.
you are using your own blog table which has a much simpler structure:
BlogID
BlogDate
Content
Title
Since your structure is much simpler, you have no need for using the C! and C2 aliases and creating the inner join
I corrected the problem by chanig the sql code:
$query_Recordset1 = sprintf("SELECT C2.ContentGroup, C2.ContentDate, C2.ContentPageSetOrder FROM pcms2_contents AS C1 LEFT OUTER JOIN pcms2_contents AS C2 ON C2.ContentPagesetParentID = C1.ContentID WHERE C1.ContentGroup = 'Blog' AND C2.ContentPageSetOrder IS NOT NULL AND (YEAR(C2.ContentDate) = %s OR -1 = %s) AND (MONTH(C2.ContentDate) = %s OR -1 = %s) GROUP BY C2.ContentPageSetOrder ORDER BY C2.ContentPageSetOrder DESC ", GetSQLValueString($passedYear_Recordset1, "int"),GetSQLValueString($passedYear2_Recordset1, "int"),GetSQLValueString($passedMonth_Recordset1, "int"),GetSQLValueString($passedMonth2_Recordset1, "int"));
to:
$query_BlogRS = sprintf("SELECT * FROM blog WHERE BlogID IS NOT NULL AND (YEAR(BlogDate) = %s OR -1 = %s) AND (MONTH(BlogDate) = %s OR -1 = %s) GROUP BY BlogID ORDER BY BlogID DESC", GetSQLValueString($passedYear_BlogRS, "int"),GetSQLValueString($passedYear2_BlogRS, "int"),GetSQLValueString($passedMonth_BlogRS, "int"),GetSQLValueString($passedMonth2_BlogRS, "int"));

