Problem with running external process

[ToMasz]

This is the result of ulimit command on my machine:

core file size        (blocks, -c) 0
data seg size         (kbytes, -d) unlimited
file size             (blocks, -f) unlimited
max locked memory     (kbytes, -l) unlimited
max memory size       (kbytes, -m) unlimited
open files                    (-n) 1024
pipe size          (512 bytes, -p) 8
stack size            (kbytes, -s) 8192
cpu time             (seconds, -t) unlimited
max user processes            (-u) 1014
virtual memory        (kbytes, -v) unlimited

It looks like either pipe size or stack size may be too low. But my
main script must be running all the time to collect data so how much
should I increase these values to allow infinite executions of external
process?