if i try to multiplay with a frien of mine we do not get connected
and get an error message as this error trackerui.dll, at home it does work on all systems we tried allot but esf will not multiplay at his place. and other mod do.
the trackerui.dll is not a problem, everybody gets that. don't worry about it.
now for why the connection doesn't happen: i'm assuming one of you is setting up a server and the other is trying to connect to it? and i see in your post that he is the one setting it up on his computer. soo .. is he behind a router/firewall? the IP he is giving you starts with 192.168. ?
if the client is behind a firewall that's not a problem. if the server behind a firewall then there could be a problem.
if the server is behind a router then u need to put it in DMZ "demetralized zone".
if it's a software firewall then u need to make sure that hl.exe has full permission to use the internet (i.e. allow incoming and outcoming connections ect ...) i can't explain how since it depends on what firewall u are using.
i'm not an expert on that, so ....
maybe u can give more info? like what kind of a fireewall u are using ect?