permissions

Hello, i need to now how to set permissions for scripts to work on another server, this is my error, and im trying to make a guest book, what do i do the change the permissions or get around this, thanks. Warning: fopen("mb.php3.comment", "a") - Permission denied in /home/nofx413/public_html/annotate.php3 on line 29 Warning: fwrite(): supplied argument is not a valid File-Handle resource in /home/nofx413/public_html/annotate.php3 on line 30 Warning: fclose(): supplied argument is not a valid File-Handle resource in /home/nofx413/public_html/annotate.php3 on line 31 here are lines 29 - 31 in the script: $fp = fopen (basename($PHP_SELF) . ".comment", "a"); fwrite ($fp, $message ); fclose ($fp);