SQL & PL/SQL

I need some help with an update query. I am trying to update hz_contact_points.email_address to append a comma then the source_email field from jtf_rs_resource_extns to it. So if the existing value in hz_contact_points.email_address field is 'tim.berry@oracle.com', and the value in source_email in jtf_rs_resource_extns is 'todd@oracle.com', the resulting value in hz_contact_points.email_address would be 'tim.berry@oracle.com,todd@oracle.com'. I have medium level sql skills. Here is the query I am trying that is not working:

update hz_contact_points g
set g.email_address = g.email_address||','||f.source_email
where f.source_email in
(select f.source_email
from hz_relationships a, hz_parties b, hz_cust_accounts d, hz_contact_points e, jtf_rs_resource_extns f
where d.party_id = a.object_id
and a.party_id = b.party_id
and e.owner_table_id = a.party_id
and e.primary_flag = 'Y'
and e.status = 'A'
and e.email_address is not null
and f.resource_id = d.attribute4
and d.account_number = 12544)

I get an error that f.source_email is an invalid identifier. I have the last statement d.account_number = 12544 to test this for just one account first - I will take it out when the sqil is correct and I want to run the update for every account.

Thanks! Tim Berry