SQL & PL/SQL

I have two databases A and B and I have to insert  some table data from database A to database B. So I do(TWO TABLE NAMES WOULD BE TABLE1(A) AND TABLE2(B))

PROCEDURE XYZ

BEGIN

INSERT INTO SCHEMA_NAME.TABLE2

SELECT( COLUMN1

               ,COLUMN2........)                               FROM  A.TABLE1;

COMMIT;

END XYZ;

BUT I AM GETTING ERRORS AS TABLE OR VIEW DOES NOT EXISTS BUT IN REALITY IT EXISTS.

HERE IS A SAMPLE CODE

PROCEDURE sp_readrecords(in_run_iIN NUMBER)

IS

    
err_i   NUMBER := NULL;

    
err_x   VARCHAR2 (500) := NULL;

BEGIN

SAVEPOINT read_records;

INSERT INTO OTS_OWN.CSXT_RAIL_PROFILE_FILE

SELECT header_g FROM TMS.OTC_RAIL_PROFILE_FILE;-------------TABLE OR VIEW DOES NOT EXIST

INSERT INTO OTS_OWN.CSXT_RAIL_PROFILE_MEASURE

SELECT track_segment_prefix_i

      ,reference_milepost_i

      ,location_offset_feet_q

      ,track_type_c

      ,rail_left_right_c

      ,height_wear_q

      ,ctog_wear_q

      ,rail_weight_q

      ,latitude_m

      ,error_s

      ,error_x

      ,last_update_d            

      FROM TMS.OTC_RAIL_PROFILE_MEASUREMENT;

1. TMS.PKG_TRUNCATE_OTC.TMS.PKG_TRUNCATE_OTC;------------ TMS.PKG_TRUNCATE_OTC MUST BE DECLARED

COMMIT;

EXCEPTION

      WHEN OTHERS

      THEN

         err_i:= SQLCODE;

         err_x:= SQLERRM;

         ROLLBACK TO SAVEPOINT read_records;

         csxp_refresh_tabs.sp_csxt_log

         (

          
in_run_i

           ,'Error in reading
CSXT_RAIL_PROFILE_OR_MEASURE records'

           ,err_i

           ,err_x

         );       

END sp_readrecords;

WHERE TMS IS ONE DATABASE AND OTS_OWN IS A SCHEMA IN OTC DATABASE