When I am trying to open Tablespaces, from
View > Tablespaces, I m getting following error
This function requires access to dba_free_space,
dba_data_files, Dba_tablespaces fragmentation requires.
What is the problem? What I need to do to solve this problem
Your current user needs access to these views.
GRANT SELECT ON :Object: to CurrentUser;
GRANT SELECT ANY TABLE TO ...
With 9i you need additionally a grant for viewing catalog objects;
GRANT SELECT CATALOG -- ore something like this, view the doc please
Check out whether you are log in as System. If you login as different user without sufficient privileges to view the SYS tables, it will throw you errors.
I hope this answer your problem.