What is wrong with this code - will not update

I am attempting to use the following code to update a column in a table :

<cfloop from="1" to="#form.totalRows#" index="row">

<cfparam name="form.PartNumberID#row#">
<cfparam name="form.deliveryNumber#row#">

<cfset PartNumberID = form["PartNumberID"& row]>
<cfset deliveryNumber = form["deliveryNumber"& row]>

<cfquery name="qryUpdate" datasource="datasource">
update TABLE
set deliveryNumber = '#deliveryNumber#'
where (Rdn = #Rdn# and PartNumberID = #PartNumberID#)
</cfquery>

</cfloop>

It appears to execute successfully without any errors. Yet when I check the sql server, the deliveryNumber column in the table is still NULL and not updated with the valued entered in the form/screen.

I have used <cfoutput> to display all the values and they all come out as they should be (I selected one record to test and the variables displayed from cfoutput all correspond to the record)

I even took the update part and ran it thru the query analyzer and plugged in/hardcoded the values from the variables and the update works, the deliveryNumber column in the table is updated. So it appears the code is working.

Yet when I run it thru the application, it does not work and does not give any errors.

Can somebody tell me what the problem is, I just cannot see it ?

Thanks