could be any one or a number of things. my first observation is that the site is really slow. took it a good 10-20 seconds to stream a 10 second flv video. so i'm going to guess that timeout has something to do with this.
some cross-questions:
do you use firefox at home?
what's the net speed at your dad's house (slower/quicker/the same as yours)?

it could be a timeout thing. i've known firefox here (even though it's supposed to be quicker than IE) timeout on sites that IE doesn't. only occasionally though. it's worth trying IE on his PC. IE is always installed, no matter what you try and do with it.
go to Start -> Run and type in 'iexplore' (less the quotes). IE will come up. try the site then and see what happens.