Session variables passing to functions

I am trying to create a page that adds property listings and then add features to the properties.

i attached the code for the page that is having issues. I have session variables turned on and here is the function and i cannot get the last listing_id in the listing table to be sent.

I have a function to find the last listingID but the addlistingfeature doesnt like the return type





<cffunction name="AddListingFeature" returntype="void">

<cfargument name="Feature_ID" type="string" required="true">
<cfargument name="Listing_ID" type="string" required="true">

<cfquery datasource="#request.realestatedata#">
Insert Into ListingsFeatures_T(Listing_ID,Feature_ID)
Values('#Trim(arguments.Listing_ID)#','#Trim (arguments.Feature_ID)#')
</cfquery>

</cffunction>