Read and write a text folder from an app

Hi,
We are currently trying to read and write a text folder from an app but each time we try to read ( or write), we have this error :

Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | PROCESS: 6184 ,TID 6184
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | SIGNAL: 11, ADDR (nil), AT 0xb6cfd804 SI_CODE 0x00000001
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | ILLEGAL ADDRESS (nil)
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | LEGATO VERSION
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | PROCESS COMMAND LINE
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | PROCESS MAP
Jan 20 14:24:58 swi-mdm9x28-wp user.err Legato: =ERR= | smsReceiver[6184] | BACKTRACE

here is what i add on the adef folder to be able to modify the text folder i created with vi :

sandboxed: false
requires:
{
file:
{
[rw] /home/coordinates/coordinates.txt
}
}

Can you describe in details the procedure to be able to modify a text folder from an app ?
Thx in advance,
Pierre

You can see here

Also you can see this