Can someone teach me about ettercap?

[lasi merum]

when i use ettercap to sniffed,the message appear below:

SEND L3 ERROR: 694 byte packet (0800:06) destined to 192.168.1.101 was not forwarded (libnet_write_raw_ipv4(): -1 bytes written (Message too long)

what happened?what does it mean?please help me!

and when i use nmap to scan one's computer,the result like this:

PORT STATE SERVICE VERSION
2717/tcp open unknown
2869/tcp open http Microsoft HTTPAPI httpd 1.0 (SSDP/UPnP)
|_ html-title: Site doesn't have a title (text/html).
3476/tcp open ssl/http Apache httpd
|_ sslv2: server still supports SSLv2


is this a windows system or not?

Please,thanks

[batbout]

try to type this in a shell

echo "1" > /proc/sys/net/ipv4/ip_forward

and tell me if this works

concerning the nmap scan you should use -O to determin which OS your target is runing