source ip spoofing option problem

Hi,
I have a problem when do compile source to binary file with source ip
spoofing.
I have finished the compiler without error, and I can see the -S option when
type sflowtool -h
But, I got a error message when I run the sflowtool -c 172.26.1.222 -d 9991
-S command , it return message " sendto returned -1 (expected 100):
Interrupted system call", and the 172.26.1.222 have not receive any
packets.
But, when I run "sflowtool -c 172.26.1.222 -d 9991" , the 172.26.1.222 have
received many packets.
Why due to this?
Platform: windowsXP SP2 with cygwin
Sflowtool version 3.12
Compile command1 : #sh ./configure --enable-source-spoofing
Compile command2: #sh ./configure CFLAGS=-DSPOOFSOURCE

eric@EricT42 ~/sflowtool312/src
$ ./sflowtool -h
Copyright (c) InMon Corporation 2000-2006 ALL RIGHTS RESERVED
This software provided with NO WARRANTY WHATSOEVER
Usage: ./sflowtool [-p port]
./sflowtool version: 3.12
forwarding:
   -f host/port - (forward sflow to another collector
                      - ...repeat for multiple collectors)
csv output:
   -l - (output in line-by-line format)
tcpdump output:
   -t - (output in binary tcpdump(1) format)
   -r file - (read binary tcpdump(1) format)
   -x - (remove all IPV4 content)
   -z pad - (extend tcpdump pkthdr with this many zeros
                          e.g. try -z 8 for tcpdump on Red Hat Linux 6.2)
NetFlow output:
   -c hostname_or_IP - (netflow collector host)
   -d port - (netflow collector UDP port)
   -e - (netflow collector peer_as (default = origin_as))
   -s - (disable scaling of netflow output by sampling
rate)
   -S - spoof source of netflow packets to input agent IP
Filters:
   +v <vlans> - include vlans (e.g. +v 0-20,4091)
   -v <vlans> - exclude vlans
=============== Advanced Tools
==============================================
| sFlowTrend (FREE) - http://www.inmon.com/products/sFlowTrend.php
|
| Traffic Sentinel - http://www.inmon.com/support/sentinel_release.php
|
============================================================================
=

eric@EricT42 ~/sflowtool312/src
$ ./sflowtool -c 172.26.1.222 -d 9991 -S
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call
sendto returned -1 (expected 100): Interrupted system call

==========================================
Stark Technology Inc.
eric.wu@sti.com.tw
Received on Fri Jun 29 02:53:14 2007