issue with new secondary index

hi i have created new secondary index in VEPO table.( mandt, werks,lgort, sonum).index is activated. but when i am doing activate and adjacent in database in SE14.it is giving warings and error.

warning 1:

Enhancement category 3 possible , but include or subty. not yet classified.

index VEPO-ZS1 must be created in the database

test activation of Table VEPO successful.

Activation and DDL statments for Table VEPO required.

warning and error:

Enhancement category 4 possible , but include or subty. not yet classified.

create UNIQUE INDEX "VEPO~ZS1' ON "VEPO" ("MANDT", "WERKS", "LGORT","SONUM")

PCTFREE 10

INITRANS 002

TABLESPACE PSAPBTABI

STORAGE ( INITIAL 0000447920 K

NEXT 0000447920 K

MINIEXTENTS 0000000001

MAXEXTENTS UNLIMITED

PCTINCREASE 0000

FREELISTS 001)

ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found

DDL time(___1): ...378,823 milliseconds

The SQL statement was not executed

Statements for Table VEPO could not be executed

Request for VEPO could not be executed

When i m executing below select staments its taking more time.

For below Select Statments i m using :

if not t_vbap[] is initial.

select venum

vbeln

unvel

vemng

matnr

lgort

sonum

werks

from vepo

into table t_vepo

for all entries in t_vbap

where matnr in s_matnr

and werks = p_werks

and lgort in s_lgort

and sonum = t_vbap-sonum.

else.

select venum

vbeln

unvel

vemng

matnr

lgort

sonum

werks

from vepo

into table t_vepo

where matnr in s_matnr

and werks = p_werks

and lgort in s_lgort.

endif.