problems with application.cfc

in my application.cfc i have the following code in my onSessionStart function:
<cfscript>
Session.started = now();
</cfscript>

then in my onSessionEnd i have the following:
<cfquery datasource="#application.dsn#">
UPDATE users
SET lastLogin = #CreateODBCDateTime(session.Started)#
WHERE username = '#session.auth.username#'
</cfquery>
<CFOUTPUT><br>Database Updated - Last Login #CreateODBCDateTime(session.Started)#<br></CFOUTPUT>

so the idea is that when the session begins, session.started stores the date/time. then when the session ends, the session start date/time is written out to the database as the "lastLogin" field.

problem is that i am not getting any errors and the value in the database is not being updated.

any suggestions?