Execute Immediate within a stored procedure keeps giving insufficient priviliges error

Oracle's security model is such that when executing dynamic SQL using Execute Immediate (inside the context of a PL/SQL block or procedure), the user does not have privileges to objects or commands that are granted via role membership. Your user likely has "DBA" role or something similar. You must explicitly grant "drop table" permissions to this user. The same would apply if you were trying to select from tables in another schema (such as sys or system) - you would need to grant explicit SELECT privileges on that table to this user.

You should use this example with AUTHID CURRENT_USER :

CREATE OR REPLACE PROCEDURE Create_sequence_for_tab (VAR_TAB_NAME IN VARCHAR2)   AUTHID CURRENT_USERIS   SEQ_NAME       VARCHAR2 (100);   FINAL_QUERY    VARCHAR2 (100);   COUNT_NUMBER   NUMBER := 0;   cur_id         NUMBER;BEGIN   SEQ_NAME := 'SEQ_' || VAR_TAB_NAME;   SELECT COUNT (*)     INTO COUNT_NUMBER     FROM USER_SEQUENCES    WHERE SEQUENCE_NAME = SEQ_NAME;   DBMS_OUTPUT.PUT_LINE (SEQ_NAME || '>' || COUNT_NUMBER);   IF COUNT_NUMBER = 0   THEN      --DBMS_OUTPUT.PUT_LINE('DROP SEQUENCE ' || SEQ_NAME);      -- EXECUTE IMMEDIATE 'DROP SEQUENCE ' || SEQ_NAME;      -- ELSE      SELECT 'CREATE SEQUENCE COMPTABILITE.' || SEQ_NAME || ' START WITH ' || ROUND (DBMS_RANDOM.VALUE (100000000000, 999999999999), 0) || ' INCREMENT BY 1'        INTO FINAL_QUERY        FROM DUAL;      DBMS_OUTPUT.PUT_LINE (FINAL_QUERY);      cur_id := DBMS_SQL.OPEN_CURSOR;      DBMS_SQL.parse (cur_id, FINAL_QUERY, DBMS_SQL.v7);      DBMS_SQL.CLOSE_CURSOR (cur_id);   -- EXECUTE IMMEDIATE FINAL_QUERY;   END IF;   COMMIT;END;/

you could use "AUTHID CURRENT_USER" in body of your procedure definition for your requirements.