Sure,
The outputs below corresponds to the "working" condition after I fixed the size of the third partition.
The problem becomes apparent in the 'fdisk info' output. All 3 existing partitions are LBA (marked CHS=254,255,255). For
 whatever reason, the program that created the third partition didn't care about making the number of sectors a multiple
 of (sectors*heads), so that the new QNX partition starts at the beginning of a cylinder.
I'm not sure whether there's a requirement that a partition must start at the beginning of a cylinder (since CHS is not 
real anyway), but if there is, not everyone is following that convention apparently (and it seems I'm not the only one 
with one of those ill-sized partitions). In any case, your installer could do one of 3 things:
a) Write the CHS as 254,255,255 and use plain LBA (should've done this, since cylinder was >1023 (?) )
b) Write the CHS value that results from converting the start sector, and if it doesn't start at the beginning of a 
cylinder, so be it
c) Abort the installation, but at least tell the user what the problem is :-)

Thanks for looking into this.
Regards,
Claudio


<fdisk show output>


   _____OS_____     Start      End     ______Number______   Size    Boot  
   name    type    Cylinder  Cylinder  Cylinders   Blocks                 

1. NTFS       7          0       7648      7649  122881122  60000 MB
2. FAT32     14       7649       7779       131   2104515   1027 MB
3. nonQNX   120       7780       7791        12    192780     94 MB
4. QNX6     179       7792      30400     22609  363213585  177350 MB   *

<fdisk info output>

Physical disk characteristics: (/dev/hd0)
    Disk type        : Direct Access (0)
    Cylinders        : 30401
    Heads            : 255
    Sectors/Track    : 63
    Total Sectors    : 488397168

Warning: total sectors field does not agree with
           cylinders*sectors/track*heads!! (488397168 vs 488392065)

Partition table information:
    0: (7) beg(h=1,s=1,c=0) end(h=254,s=255,c=255) off=63, size=122881122
    1: (14) beg(h=254,s=255,c=255) end(h=254,s=255,c=255) off=122881185, size=2104515
    2: (120) beg(h=254,s=255,c=255) end(h=254,s=255,c=255) off=124985700, size=192780
    3: (179) beg(h=0,s=193,c=255) end(h=254,s=255,c=255) off=125178480, size=363213585
signature1=0x55, signature2=0xAA


<pci output>

PCI version    = 2.10

Class          = Multimedia (RAM)
Vendor ID      = 8086h, Intel Corporation 
Device ID      = 269ah,  631xESB/632xESB High Definition Audio Controller
PCI index      = 0h
PCI Mem Address = fbffc000h enabled
PCI Int Pin    = INT A
Interrupt line = 11
CPU Interrupt  = bh

Class          = Mass Storage (IDE)
Vendor ID      = 8086h, Intel Corporation 
Device ID      = 269eh,  631xESB/632xESB IDE Controller
PCI index      = 0h
PCI IO Address  = 1f0h enabled
PCI IO Address  = 3f4h enabled
PCI IO Address  = 170h enabled
PCI IO Address  = 374h enabled
PCI IO Address  = ffa0h enabled
PCI Int Pin    = INT A
Interrupt line = 11
CPU Interrupt  = bh

Class          = Mass Storage (Serial ATA)
Vendor ID      = 8086h, Intel Corporation 
Device ID      = 2681h,  631xESB/632xESB SATA AHCI Controller
PCI index      = 0h
PCI IO Address  = fe00h enabled
PCI IO Address  = fe10h enabled
PCI IO Address  = fe20h enabled
PCI IO Address  = fe30h enabled
PCI IO Address  = fec0h enabled
PCI Mem Address = ff970000h enabled
PCI Int Pin    = INT C
Interrupt line = 9
CPU Interrupt  = 9h

Class          = Mass Storage (SCSI)
Vendor ID      = 1000h, LSI Logic / Symbios Logic 
Device ID      = 54h,  SAS1068 PCI-X Fusion-MPT SAS
PCI index      = 0h
PCI IO Address  = cc00h enabled
PCI Mem Address = f7dec000h enabled
PCI Mem Address = f7df0000h enabled
PCI Expansion ROM = f7e00000h disabled
PCI Int Pin    = INT A
Interrupt line = 11
CPU Interrupt  = bh

Class          = Display (VGA)
Vendor ID      = 10deh, nVidia Corporation...