I am trying to load S. pombe genome on IGV in Ubuntu! Eventually when the software started on the bottom right it was 310M of 891M, but now after 30 minutes its just 329M. Is it supposed to be like this? I have a high speed internet connection!
I'm not sure why you can't load it from the server, but you can try loading it in from a reference file to the genome. If you go here, download the files as zip, unzip, go to IGV and "Load Genome From File", select the .genome in the unzipped directory, it seems to load it fine.