This is a closed modpack, so I'm going to have to redact some of the information I show.
It says the following when I select the pack:
InstalledPack{info=PlatformPackInfo{name='[Modpack]', displayName='[Modpack]', url='https://dl.dropboxusercontent.com/u/54014114/[Modpack].zip', icon=null, logo=net.technicpack.launchercore.restful.Resource@18879c56, background=net.technicpack.launchercore.restful.Resource@6f28deae, minecraft='1.6.2', forge='null', version='1.0', solder='', forceDir=false}, name='[Modpack]', platform=true, build='recommended', directory='launcher[Modpack]'}
When I download it:
Valid:
Starting download of https://dl.dropboxusercontent.com/u/54014114/[Modpack].zip, with 3 tries remaining
And that's it.
If I tell it to Launch after having done this, it starts the process anew. This is the stuff that happens to the progress bar beneath the news feed:
__% [modpack]-1.0.zip (Runs until completion, go to step 2)
(Unpacking various assets, such as Millénaire and mATMOS)
(Progress bar vanishes.)
It's not even explaining that something is wrong. It just says "Downloading. Unpacking. Welp, my work here is done... Zzzz.".