IF statement inside another IF statement, using excel vba, give type error

I use excel vba and IF statement inside another IF statement, by this code

LastRow = GetRowCnt

For bl = LastRow To 5 Step -1

    If Range("I" & bl).Value = "RTV CLOSE" Then
        Range("S" & bl) = "NRC-Scrap"
        Range("AC" & bl) = Range("BF" & bl)
        Range("AD" & bl) = Range("BF" & bl)
        If Range("CD" & bl).Value = "8" Then
            Range("BV" & bl) = "Scrap-17-Other Scrap Vendor_VENDOR"
        ElseIf Range("CD" & bl).Value = "1" Then
            Range("BV" & bl) = "Scrap-14-CID_ODM_VENDOR"
        End If
    End If

Next

When I run Only first IF, it goes well, but when I add second IF it writes

Run-time error '13': Type mismatch.

I really don't know when I have mistake, Any idea?

Thank you