Oracle Database Discussions

Hi All
I am facing the below problem and have not been able to get it solved with the help of Unix administrator till now (on the assumption that it might be a directory permission related problem)

Following code is trying to create a file in host server directory :
....
v_os_touch_file := utl_file.fopen('EXTERNAL_DIR', file1.txt, 'w');
.....

We are getting the below error every-time :

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

select * from v$version
-----------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bi
PL/SQL Release 10.2.0.3.0 - Production
"CORE 10.2.0.3.0 Production"
TNS for IBM/AIX RISC System/6000: Version 10.2.0.3.0 - Productio
NLSRTL Version 10.2.0.3.0 - Production

Please help in this.

Thanks a lot.