Unknown column 'X' in 'where clause'

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Jeg får 1 ud af 100 gange følgende fejl: "Unknown column 'X' in 'where clause'"

    ' Update the replies if appropriate
    strSql = "SELECT R.CAT_ID, " & _
        "R.FORUM_ID, " & _
        "R.TOPIC_ID, " & _
        "R.REPLY_ID, " & _
        "R.R_STATUS, " & _
        "R.R_DATE as Posts_Date, " & _
        "M.M_NAME, " & _
        "M.MEMBER_ID " & _
        " FROM " & strTablePrefix & "REPLY R, " & strMemberTablePrefix & "MEMBERS M" & _
        " WHERE (R.R_Status = 2 OR R.R_Status = 3) " & _
        " AND R.R_AUTHOR = M.MEMBER_ID "
    if ModLevel <> "BOARD" then
        if ModLevel = "CAT" then
            strSql = strSql & " AND R.CAT_ID = " & CatID
        elseif ModLevel = "FORUM" then
            strSql = strSql & " AND R.FORUM_ID = " & ForumID
        elseif ModLevel = "TOPIC" then
            strSql = strSql & " AND R.TOPIC_ID = " & TopicID
        else
            strSql = strSql & "AND R.REPLY_ID = " & ReplyID
        end if
    end if
    set rsLoop = my_Conn.Execute (strSql)