One dynamic drop down

Hi everyone.

I have a page that has 2 dynamic drop down menus in that depending what is selected in the first drop down will display certain criteria in the 2nd drop down. I have this working in one table just fine, but then I tried it in another table and I can't get the code to work for some reason. I can choose the first drop down menu, but then it has a timed out error that displays after I make my first choice. I can't see the Cold Fusion error, so I'm not sure what's wrong. Here's what I have in my table called Elastomer_Cut_Size:

Column Name                    Data Type

ItemID                                   Int

Elastomer Part_Number     nvarchar(50)

X_mm                                   Int

Y_mm                                   Int

Elastomer_Cost                    Money

Cutting_Cost                         Money

K_Factor                            numeric(18,1)

Sell_Price                              Money

Here's the code I have:

<!--- store the selected Main_Group variable variable after the first select boxes submits itself --->

<cfif isDefined('form.select_Elastomer_Part_Number')>

    <cfset page.select_Elastomer_Part_Number = form.select_Elastomer_Part_Number>

</cfif>

<cfoutput>

  <form name="DropDown" method="post">

  <!--- query DB for the first drop down list --->

  <cfquery name="get_Elastomer_Part_Number" datasource="#application.DataSource#">

     SELECT DISTINCT Elastomer_Part_Number

     FROM Elastomer_Cut_Size

     ORDER BY Elastomer_Part_Number

  </cfquery>

  <!--- first drop down list --->

  <!--- NOTICE the onChange javascript event in the select tag, this is what submits the form after the first selection --->

  <select name="select_Elastomer_Part_Number" required="yes" onchange="this.form.submit()">

     <option>Select Part Number</option>

     <!--- dynamically populate the first drop down list based on the get_Part_Number query --->

     <!--- NOTICE the CFIF within the option tag, this says, if the first selection has been made, display the chosen option when the page reloads --->

     <cfloop query="get_Elastomer_Part_Number">

         <option value="#Elastomer_Part_Number#" <cfif isDefined('form.select_Elastomer_Part_Number')><cfif form.select_Elastomer_Part_Number eq "#Elastomer_Part_Number#">selected</cfif></cfif>>#Elastomer_Part_Number#</option>

     </cfloop>

</select>

<p>

<!--- if the first selection has been made, display the second drop down list with the appropriate results --->

<cfif isDefined('page.select_Elastomer_Part_Number')>

   <!--- query DB for second drop down list, based on the selected item from the first list --->

   <cfquery name="get_Y" datasource="#application.DataSource#">

        SELECT DISTINCT Y_mm

        FROM Elastomer_Cut_Size

        WHERE Elastomer_Part_Number = #page.select_Elastomer_Part_Number#

        ORDER BY Y_mm

   </cfquery>

   <!--- second drop down list --->

   <select name="select_Y" required="yes">

      <option>Select Y</option>

      <!--- dynamically populate the second drop down list based on the get_X query --->

      <cfloop query="get_Y">

         <option value="#Y_mm#">#Y_mm#</option>

      </cfloop>

   </select>

</cfif>

</form>

</cfoutput>

Can anyone tell me what I'm doing wrong? When I try to run a query for the 2nd drop down is when I have problems.I actually don't even need another drop down to display. I just want whatever part number is chosen in the first drop down, to run a calculation. Each part number has a different calcualation. I can get this to work if I just choose a Part number and display some text under the cfif isDefined('page.select_Elastomer_Part_Number'). But if I try to put a CFQuery after this isDefined, the timed out error displays. Can someone please help me? Thanks.

Andy