Since it’s making it to partially through the downloads it seems that the proxy might not be the issue. The problem might just be general slowness in the Eclipse mirror network as Eclipse 3.5 is replicated (that’s going on today) as well as the load
on our download servers due to the 7.5 release.
To get around all that I’d suggest you try downloading the MyEclipse 7.5 “all-in-one” installer for your platform. The ‘all-in-one’ installers don’t need to use the Internet for any downloads so they bypass any transient network slowness issues.
Please install 7.5 into a different location than 7.1 so you can test it easily. Once you’re happy with it you can run the uninstaller for 7.1 if you like. Please let us know if you run into any other issues or have any further questions.