[syslinux] boot disk failure

[Pascal Legrand]

Hello,

i've got a problem with boot pxe on pc, all my pc works fine except in a room 
where all the same pc doesnt works :
my configuration (dhcp tftp etc...) works fine also

here is a part of my tftpboot directory

ghost/
memdisk
menu.c32
pxelinux.0
pxelinux.cfg/

./ghost:
ghost288.IMA
ghost_geii_101.IMA
ghost_MM.IMA
ghost_MM.IMA.old

./pxelinux.cfg:
default

here is a part of my default file

DEFAULT menu.c32

TIMEOUT 300
ALLOWOPTIONS 0
PROMPT 0

MENU TITLE MENU

LABEL BootNormal
         MENU LABEL Boot local
         MENU DEFAULT
         LOCALBOOT 0

LABEL ghost
         MENU LABEL Ghost
         kernel memdisk
         append initrd=ghost/ghost288.IMA

LABEL ghost_GEII
         MENU LABEL Ghost GEII-101
         kernel memdisk
         append initrd=ghost/ghost_geii_101.IMA

LABEL ghost_multimedia
         MENU LABEL Ghost Multi-Media
         kernel memdisk
         append initrd=ghost/ghost_MM.IMA


when the pc boot, the dhcp request works fine, the "download" of ghost288.ima, 
works fine also.
when it try to launch the os i've got a message :

loading memdisk...
loading ghost/ghost_geii_101.ima..............ready
memdisk 3.70
...
...
...
...
...
.
loading boot sector...booting...
Boot disk failure

i've got another room with pc with the same network card wich works fine with 
the same image


any idea to help me ?



thank you