How to configure wingate 4xx

On a small network of win98 machines, the pc connected with internet (dialup) has wingate 4.3 installed on it. While anybody tries to play yahoo games pool or literati he finds himself unable to play and receives a messege telling that he is behind a firewall, while rest of the yahoo games run properly. This is probably because of some wingate settings/configuration. Can anybody tell me what changes are to be made to wingate, so that these games can run on client machines also.