To Solve this error you could use more than one solution :
Solution One :
Solution One :
declare
begin
for index_rec in (select owner, index_name
from dba_INDEXES
where status = ‘UNUSABLE’)
loop
execute immediate ‘alter index ‘ || index_rec.owner || ‘.’ ||
index_rec.index_name || ‘ rebuild’;
end loop;
end;
Solution two:
10g and above :
alter system set skip_unusable_indexes=true;
thank you
Osama mustafa