🚀 go-pugleaf

I'm getting the error:

tar: Can't write to (null) : Permission denied

as follows:

tar -v -f /dev/rst8 -c -G /jeff/xprogs/xzap
gtar: Directory /jeff/xprogs/xzap/1.0 is new
gtar: Removing leading / from absolute path names in the archive.
jeff/xprogs/xzap/
jeff/xprogs/xzap/1.0/
jeff/xprogs/xzap/1.0.tar.Z
gtar: Can't write to (null) : Permission denied

Is there a bug with the "-G" option in tar.1.10 ? On -G, tar.c:options() does

		case 'G':
			...
			f_gnudump++;
			gnu_dumpfile=0;		(tar.c:448)

create.c:create_archive() does

        if(f_gnudump)
                write_dir_file();	(create.c:204)

but gnu.c:write_dir_file() does:

        fp=fopen(gnu_dumpfile,"w");
        if(fp==0) {
                msg_perror("Can't write to %s",gnu_dumpfile);
                return;
        }				(gnu.c:183)

Thanks,