Error on page

[Silju Augustine]

I am trying to update a record. It correctly opens the record first. but when i try to update it shows the error "Microsoft VBScript runtime (0x800A01A8)
Object required: ''
in line No 20"

this is the code that i used
Kindly help

<form method="post" action="heading .asp">

<% n1=request(trim ("n1"))
n2=request(trim ("n2"))
n3=request(trim ("n3"))
n4=request(trim ("n4"))
n5=request(trim ("n5"))
n6=request(trim ("n6"))
n7=request(trim ("n7"))
n8=request(trim ("n8"))
n9=request(trim ("n9"))

DIM sd
dim rs
Set sd = Server.CreateOb ject("ADODB.Con nection")
sd.ConnectionSt ring = "Provider=Micro soft.Jet.OLEDB. 4.0;Data Source=" & _
Server.MapPath ("/logon.mdb") & ";"
sd.Open
set rs=sd.execute(u pdate students set DOB='"&n2&"',SN ame='"&n9&"',Cl as="&n3&",Sec=' "&n4&"',"FName= '"&n5&"',MName= '"&n6&"',Adrs=' "&n7&"',Phone=' "&n8&"' where AdmNo="&n1&")
%>
<center>
<input type="submit" value="!Success fully Saved!">