From The developer "NaGA" Subject: Re: LibNet nolonger works well with ettercap, many users (All?) hit into this error due to newer libnet installations. Date: Tue, 25 Sep 2007 09:43:02 +0200 (CEST) Ettercap support has been dropped 2 years ago. Sorry, but there won't be any change for this. If someone finds a solution for this by his own, we will pleased to add the patch on the website for download.
A fork is needed to continue this useful project.