Except for the occasional update of the "X of Y downloaded" (or "extracted") text, there's no indication that the installer is doing anything while downloading, and it appears as if it's crashed.
One user has claimed the installer crashes when he tries to use it; as he was able to see the list of level packs, this suggests the crash comes only when the download was actually started. This means there's a good chance it hadn't actually crashed, but it was just this issue.
Workaround: None needed. The installer is working, it just doesn't respond properly to user input / system messages while downloading. But this needs to be fixed for user-friendliness reasons.