Sqlcmd On SQL EXPRESS: Access Denied During CREATE DATABASE Command

Scenario:

I have installed SQL Express 2005 and I want to create a new DB using sqlcmd.



I am running a command like: sqlcmd -i file.ini (I am logged like Administrator of PC)

the content of the file.ini is:



-- Get the SQL Server data path
DECLARE @data_path nvarchar(256);

SET @data_path = 'c:Program FilesMyTestdatabase'



-- execute the CREATE DATABASE statement
EXECUTE ('CREATE DATABASE DataCollection ON
( NAME = DC_dat,
FILENAME = '''+ @data_path + 'DC.mdf'',
SIZE = 10,
MAXSIZE = 50,
FILEGROWTH = 5 )
LOG ON
( NAME = DC_log,
FILENAME = '''+ @data_path + 'DClog.ldf'',
SIZE = 5MB,
MAXSIZE = 25MB,
FILEGROWTH = 5MB )'
) ;
GO



I obtain this error:

Msg 1802, Level 16, State 4, Server TESTQ5SQLEXPRESS, Line 1
CREATE DATABASE failed. Some file names listed could not be created. Check related errors.
Msg 5123, Level 16, State 1, Server TESTQ5SQLEXPRESS, Line 1
CREATE FILE encountered operating system error 5(Access is denied.) while attempting to open or create the physical file 'c:Program FilesMyTestdatabaseDC.mdf'.


If I change the security of directory database (I add "modify" permission to Users windows group) the error disappear.

I am logged like Administrator... why is it necessary to change directory permission?