Bro ,

where clauses varchar are case sensetive .

SELECT * FROM ROLE_TAB_PRIVS WHERE ROLE = 'ACCOUNTANT';

<<select *from author>>

You are logged in as AMARTIN so it is looking under AMARTIN schema for an object names author which doe not exists . You could solve the following by 2 ways .

1. select * from schema_name.table_name ;

in your case I believe author is a table but you need to know the schema name.

or

2. Create public or private synonym author for schema_name.author;

and try your statement select * from author;

Hope this works

Good Luck