I am trying to connect my IDE 6.3.2 under windows to my target board through pdebug upon serial port. Steps below:
1) First try a target of desktop PC with Nutrino installed. It's successful.
2) Second, build an OS image on the desktop PC using the attached build file, then write the image file to floppy disk. 
Commands follow:
     mkifs -v debug.build debug.ifs
     dinit -f debug.ifs /dev/fd0
3) Reboot the desktop through the floppy disk, it boots up successfully without error.
4) Try to connect to the desktop target again, the error messages are:

MsgNak received - resending
MsgNak received - resending
MsgNak received - resending
Remote exhausted 3 retries.
MsgNak received - resending
MsgNak received - resending
MsgNak received - resending
Remote exhausted 3 retries.
MsgNak received - resending
MsgNak received - resending
MsgNak received - resending
Remote exhausted 3 retries.
mi_cmd_stack_list_frames: No stack.
info tidlist
Undefined info command: "tidlist".  Try "help info".
set remotebaud 57600
upload C:/QNX632/prac-workspace/Hello/x86/o-g/Hello_gxx11520.tmp /tmp/Hello_g
set qnxremotecwd /tmp
Warning: /cygdrive/c/QNX632/prac-workspace/Hello/C: No such file or directory.
Warning: /QNX632/prac-workspace/Hello/.settings: No such file or directory.
Warning: /cygdrive/c/QNX632/prac-workspace/Hello/C: No such file or directory.
Warning: /QNX632/prac-workspace/Hello/x86: No such file or directory.
Warning: /cygdrive/c/QNX632/prac-workspace/Hello/C: No such file or directory.
Warning: /QNX632/prac-workspace/Hello/x86/o-g: No such file or directory.
MsgNak received - resending
MsgNak received - resending
MsgNak received - resending
Remote exhausted 3 retries.
MsgNak received - resending
MsgNak received - resending
MsgNak received - resending
Remote exhausted 3 retries.
Remote (spawn error): Exec format error.

5) I cheked the directory "\tmp" on the target, there is only an empty file (size 0) "Hello_g".
6) Anything missing when building the OS image?

Thanks
Weiming