LogMiner: utl_file_dir

Hi all,
I need some suggestions on how to set the utl_dir_file parameter in O9i. I tried to set by 'alter system set...'
but it returns error
"ORA-02095: specified initialization parameter cannot be modified"
Somebody please help me here as i need to practice on LogMiner.

TIA,

In 9.2, you can use logical directories if you want to read an OS file. Meaning you don't have to bounce the instance and change UTL_FILE_DIR.