This is an error you get when you try and connect(2) or bind(2) a socket to an address where that address doesn't make sense. For example trying to bind a socket created with PF_INET (Protocol Family Internet) to a AF_UNIX (Address Family Unix Domain Socket) address, it just doesn't make sense. Alternatively you forgot to fill in the sin_family or uin_family field in your address structure. Either way the programmer screwed up.
5 pages link to EAFNOSUPPORT:
lib/main.php:944: Notice: PageInfo: Cannot find action page