After install Firebird 1.5, i've the following dir structure

C:\Program Files
+ Firebird
+ Firebird_1_5

Inside, i've created "ExternalFiles" Directory

C:\Program Files
+ Firebird
+ Firebird_1_5
+ ExternalFiles

In Firebird.Conf, i set

ExternalFileAccess = Full ExternalFiles
UdfAccess = Full ExternalFiles

when try to create

CREATE TABLE PLANO EXTERNAL FILE 'C:\ESS062192561451-01.Txt'
(
APELLIDO1 VARCHAR (25) CHARACTER SET NONE COLLATE NONE,
APELLIDO2 VARCHAR (25) CHARACTER SET NONE COLLATE NONE,
NOMBRE1 VARCHAR (25) CHARACTER SET NONE COLLATE NONE,
NOMBRE2 VARCHAR (25) CHARACTER SET NONE COLLATE NONE,
FEC_NAC DATE);


the following message appears

" ACCES TO EXTERNAL FILE 'ESS062192561451-01.Txt' IS DENIED BY SERVER
ADMINISTRATOR"

What's wrong ?