HELP

Hi 

I need help in this matter

The error which i get is this 

Element A is undefined in FORM.

cfusion/wwwroot/ADD_DENEME.cfm: line 42

<form name="add_deneme" method="post" >
<table border="3">
<tr>
<td><strong>Musteri ID: </strong></td>
<td><input type="text" name="a" id="a" required="yes" >
</td></tr><br>
<tr>
<td><strong>Musteri Hareket Aciklama: </strong></td>
<td><input type="text" name="b" id="b" required="yes"> </td></tr>
<br>

<tr>
<td><strong>Musteri Tipi: </strong></td>
<td><input type= "text" name="c" id="c" required="yes"></td>
</tr>
</table>
<br><input type="submit" name="Kaydet" value="KAYDET">
</form>

<cfif IsDefined("form.a")>
<cfquery datasource= "DENEME" >

INSERT INTO MusteriHareketleri (MusteriId,Aciklama,musteriTipi)
values (
<cfqueryparam cfsqltype="cf_sql_integer" value="#form.a#">,
<cfqueryparam cfsqltype="cf_sql_varchar" value="#form.b#">,
<cfqueryparam cfsqltype="cf_sql_varchar" value="#form.c#">
)
</cfquery>
<cflocation url="http://127.0.0.1:8500/ADD_DENEME.cfm" addtoken="false">
</cfif>
<cfquery name="ADD" datasource="DENEME">
select * from MusteriHareketleri ;
</cfquery>
<cfquery name="update" datasource="DENEME">
UPDATE MusteriHareketleri
SET
MusteriId,
Aciklama="#form.b#",
musteriTipi="#form.c#"
WHERE
MusteriId="#form.a#"
</cfquery>
<cfdump var="#add#">