Critical: CF page inserting email newsletter signups multiple times

Hello,

We're running CFMX 6.1 on Win2003 Servers with Oracle 8.0.3 DB on UNIX. This is bad for me so I'm offering the maximum points.  

We have free projects available on our website in exchange for a consumer signing up for our email newsletter.  Somewhere along the way between say almost 2 years ago and just recently I made some kind of change that is allowing duplicate email names to be entered although the CFQUERY is supposed to check to see if the email_address is already in the database.  The weird thing is that I see the time of creation is so close together that it seems like the consumer couldn't have clicked the submit button that many times so quickly, for example:

EMAIL_NEWS_LIST_ID EMAIL_ADD            TO_CHAR(DATE
------------------ ---------------------------------------------  -----------
            150382 anonymous@yahoo.com      15:40:39 PM
            150383 anonymous@yahoo.com      15:40:40 PM
            150384 anonymous@yahoo.com      15:40:42 PM
            150385 anonymous@yahoo.com      15:40:41 PM
            150386 anonymous@yahoo.com      15:40:47 PM

When I just go to the page on my website and try to access the project by giving it my email address it does the right thing which is to check that I'm in the DB and since I am already there it does not add me again but just puts the cookie on my machine so that I can view the projects.

Here is my CF code.
<cfset date_created = CreateODBCDateTime(now())>

<!--- first check to see if the emailAdd from the form is in the DB --->
<cfif IsDefined("Form.emailAdd")>
      <cfset email_Add=Lcase(Form.emailAdd)>
            <cfquery datasource="#secondaryDS#" name="checkEmail">
                  select email_news_list_id, email_add
                  from            email_list
                  where            lower(email_add)=lower('#Form.emailAdd#')
            </cfquery>
</cfif>

<!--- if emailAdd is in DB set status to 1 and cflocate to page --->      
<cfif Form.emailAdd EQ checkEmail.email_add>
      <cfcookie name="inEmailList" value="Y" expires="never">
      <cflocation url="index.cfm?page=section/classroom/sewprojects/EraBonnet/eraBonnet.cfm">
<cfelse>
<!--- otherwise set emailStatus to 2 and add to DB, this will trigger proper message below --->
      <cfset emailStatus = 2>
      <cfset email_Add = "#Form.emailAdd#">
      <cftransaction>
            <cfquery name="addToEmailList" datasource="#secondaryDS#">
                  declare nk int;
                  
                  begin
                  
                  update next_key
                  set next_key = next_key + 1
                  where table_name = 'email_list';
                  
                  select next_key + 1 into nk
                  from next_key
                  where table_name = 'email_list';
                        
                  insert into email_list(
                        email_news_list_id,
                        email_add,
                        first_name,
                        last_name,
                        spanish_lang,
                        date_created,
                        promo_code
                  )
                  values(
                        nk,
                        '#Lcase(email_add)#',
                        '#first_name#',
                        '#last_name#',
                        '1',
                        #date_created#,
                        #promo_code#
                  );
                  end;
            </cfquery>
      </cftransaction>
      <cfcookie name="inEmailList" value="Y" expires="never">
      
      <!-- Run email reply -->
      <cfmail from="Newsletter@anonymous.com" to="#email_Add#" subject="Anonymous Co." server="#WEBMAIL_EMAIL_SERVER#">
Hello #email_Add#

Welcome to our newsletter.

      </cfmail>
      
<cflocation url="index.cfm?page=section/classroom/sewprojects/EraBonnet/eraBonnet.cfm" addtoken="no">
</cfif>
_______________________
Many thanks in advance,
Jerry