Try :

CREATE PUBLIC DATABASE LINK "NEWS_DBLINK"
CONNECT TO "NEWS_OWNER.WORLD" IDENTIFIED BY "sid8" USING 'LOUISE_NEWS'

OR

CREATE PUBLIC DATABASE LINK "NEWS_DBLINK"
CONNECT TO "NEWS_OWNER.HEROLD.COM" IDENTIFIED BY "sid8" USING 'LOUISE_NEWS'

I forget exactly which syntax it wants, but it is getting
confused because of the domain name. Play around with it
a bit and please post whichever one works when you find out
so the rest of us can remember!

-John