SQL & PL/SQL :: Writing Data To A Network Shared Folder / ORA-29283 / Invalid File Operation

I am trying to write data to a network shared folder. When I write to a local file it works perfectly. Below is my procedure.

CREATE OR REPLACE procedure nbpsbp_file as
type r_cursor is ref cursor;
refr r_cursor;
tab_name varchar2(20):= null;
tab_name1 varchar2(20) := null;
tab_name2 varchar2(20) := null;

[code]....

When I execute the above procedure, it gives me the following error

ORA-29283: invalid file operation
ORA-06512: at "SYS.UTL_FILE", line 475
ORA-29283: invalid file operation
ORA-06512: at "NBPSBP_FILE", line 36
ORA-06512: at line 1

I have also set the parameter utl_file_dir = '\10.16.10.225 emp' When I set the utl_file_sir to a local folder, for example, c: emp, and use the same path in UTL_FILE.FOPEN, then it works fine and writes the desired output to text file. But when I give it a network address, it raises the above error.