Were you trying it between 2 people with the same OS Whiskas?
I havent seen that particular message but for some reason if you are trying to use it with someone on XP,and if I remember correctly you are on 98,then it will only work if you initiate the contact.If XP tries to contact 98 it fails.
Prior to attempting to contact anyone did the system check and set up your audio and video correctly or did problems occurr during this?