Ok, let me explain what's happening with the whole launching vanilla thing.
When I get your pack, either new or an update, I check the permissions, then I have to build it for the repo. The repo needs the zip file with the instance in a specific place. It also needs that images in another folder. Then it needs an xml file with all the information about the pack so that launcher can display it. So, I get all that, for 20+ packs that need to be uploaded, and upload it all to the repo. This usually adds up to a gig or more of data, so it takes some time. When it's on the repo, 2 things are done. First the repo copies the files to the
other download repos. For a gig of data this takes some time, though not all that long, maybe an hour or three. But then, or maybe first, it calculates the MD5 hash of the zip and stores it on each server. I usually wait a while to upload the xml files so this process has some time to happen and the launcher hopefully doesn't try to download something that isn't there.
So here's what can go wrong. If the zip file hasn't gotten copied to the other servers yet, the launcher will try to download it, download nothing, then download the vanilla minecraft jar and just run that. Alternatively, if the zip is there, but the MD5 isn't, the launcher downloads it, but then can't validate that it is the correct file and doesn't unzip it. Then same as above it downloads vanilla and runs that. Both these problems are solved by just waiting for the repo to catch up.
I have extended the upload period to end friday(see above post) for exactly this reason. I will try to do some more thorough checking to make sure both the zip and MD5 are in the right places before updating the xml and letting the launcher update each pack.
