Could you also try the following:

traceroute -n 210.48.107.133
If traceroute is on your tivo it'll show if you tivo can get out.

and

wget http://210.48.107.133/index.htm
If this work and you get a index.htm file (which you can delete)
then your networking is working.

And
wget http://210.48.107.133:8000/index.htm
Which should bypass your ISP's proxy.