A bit more information would help...
What flavor of UNIX?
Is this a shell script or C program?
If shell script, what shell (sh, ksh, bash, csh)?
In shell's such as bash and ksh, if you execute another
shell script, a new shell is spawned to execute it and
your "trap"s are set to their original values when a child process
is created.
In general, child processes that dump core should return
the value of 127+signal
I don't know if any of this helps but if you can provide more
details of what you have, maybe I (and others) can be of more
help.