Hi,
the current version (2.0.4.win) of zabbix_sender crashes if you are using the realtime mode (-r, --realtime).

You are using the function setvbuf() in zabbix_sender.c:386 without buffer and buffersize = 0. If you set the buffer to NULL you have to give a buffersize for internal allocation. The value 1024 works for me.

Best regards,
Bastian Born