Retrieve Info From Multiple Databases / Insert Into Central Database Via Database LINKS

I am trying to retrieve info from multiple DBs and insert into a central DB via DB LINKS.The links are retrieved via a cursor.

However I keep coming up against 'PL/SQL: ORA-00942: table or view does not exist'..how to handle db_links using a cursor in a pl/sql block? The code is as follows:

DECLARE
db_link_rec VARCHAR2(30);
CURSOR db_link_cur IS
SELECT DB_LINK
from MESSAGING_PROD_LIST;
BEGIN
OPEN db_link_cur;
LOOP
FETCH db_link_cur INTO db_link_rec;
EXIT when db_link_cur%NOTFOUND;
[code]....