I am using Ubuntu 10.10 64 bit, and I can browse the internet fine. I am typing this using the machine. When I attempt to use the Ubuntu Update Manager to update to 11.04, I get this error message: Failed to Fetch Fetching the upgrade failed.There may be a network problem. And when I try to change servers, here is what I get: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/maverick/main/source/Sources.gz 404 Not Found [IP: 91.189.91.15 80] It repeats with other lines, 404 not found. Some index files failed to download, they have been ignored, or old ones used instead. Any ideas?