HELP! I blocked the worng image server!

[ej2k]

Using the "block images from this server" option 
(which I like and has sped up browsing a lot) on 
an ad banner, I clicked it before I realized it 
was a local banner (on the system I was accessing) 
so now ALL images from that server are blocked 
(Intellicast, which I use to watch weather maps).

How can I unblock this server?

Thanks!

Ed