for fifa 2008 u need to check the firewall settings try to disable it.
also delete the fifa 2008 exceptions from the exceptions list in the firewall settings if u see any.
if it is not working go to direct IP connection create a new one for the other computer by it's ip address and put any name then let the other click on host and u mark on his ip from the one u created then connect it should be working very good.
u have to know if lost connection once u both have to quit the game then restart it once again it is very important thus the pc remove in wrong data from the cache.
to get the ip go to >>>>start menue then run type cmd then enter then type ipconfig then enter it sould be in the first line says ip address and should be something like 192.168.2.3
Have fun if u have any problems post again we'll try another solution to fix it there is more than millions of errors should occured in network gaming don't worry we all have problems like this.