how to use GDB for cross devp env in QNX6.2

I am trying to use GDB to debug the core file. From the target i
copied that to the host server. Eneterd the gdb. i am getting the
below lines

This GDB was configured as “–host=i386-pc-nto-qnx
Program terminated with signal 11, Segmentation fault.
#0 0x00000000 in ?? ()
I tried to set the breakpoint and then gave cmd as “run”
below error i am getting
“Don’t know how to run”. i want to know exactly how to run
the code when we get core dump. Its multithreaded appln.
Thanks in advance.