A030_00.iear contains the following:

Main header:
Offset	Size	Contents
0x00	0x04	magic bytes "MAIN"
0x04	0x04	0x39
0x08	0x04	0x00
0x0C	0x04	0x00
Subheader
0x00	0x04	magic bytes "JTBL"
0x04	0x04	Number of Words following this header
0x08	0x04	0x00
0x0C	0x04	0x00
List of Words:
[File offset relative to file start][Size]...
End header
0x00	0x04	magic bytes "ENDT"
0x04	0x04	0x00
0x08	0x04	0x00
0x0C	0x04	0x00

The files referenced themselves seem to be common Nintendo files: http://llref.emutalk.net/nds_formats.htm

A0117.SAD: Not much info, could mean anything basically.

utility.bin:

Start of file
Offset	Size	Contents
0x00	0x04	Start of name table
0x04	0x04	Size of following name table
0x08	0x04	Start of pointer table
0x0C	0x04	Size of pointer table
Name table
0x00	0x04	Begin of folder names
0x00	0x04	??
0x04	0x04	Begin of Folder 1 names
0x08	0x04	??
...
Name format: [Folder bit|Length][Name] Folder only: [Pointer table number][??] Folder bit is bit 7
Pointer table
Table format: [Start offset][End offset+1]...

So you can go pretty much from there. utility bin may follow the general nds file system, so you may want to find a guide on that; I couldn't locate one quickly.

cYa,

Tauwasser