ORA-04021: timeout occurred while waiting to lock object

Fallowing piece of code get above error when running table with 65 million records.

any clue?

!!!Error occurred while executing Plsql Block at 15-OCT-15 19:22:22
DECLARE

   CURSOR get_con_removed_records IS
      SELECT rowid
      FROM project_snapshot_data_tab
      WHERE transaction_currency_code IS NULL
      AND connection_removed = 'TRUE';

   TYPE project_snapshot_data_ IS TABLE OF get_con_removed_records%ROWTYPE INDEX BY BINARY_INTEGER;
   project_snapshot_data_tab_ project_snapshot_data_;

   bulk_limit_ NUMBER := 100000;

BEGIN
   IF NOT Database_SYS.Is_Db_Patch_Registered('PROJBF', 118986) THEN
      OPEN get_con_removed_records;
      LOOP
         FETCH get_con_removed_records BULK COLLECT INTO project_snapshot_data_tab_ LIMIT bulk_limit_;