Hey guys, thanks for reporting this, and as Rev said, I am terribly sorry for the inconvenience here. So, here's what's been going on, evidently -- I now suspect this may have been what happened with 1.005.
Apparently, FileFront sometimes corrupts the files you upload to it (!?!). This morning I tried the 1.013 installer that I had on my local drive, and it worked fine. Then I downloaded the game from FileFront and tried that version -- completely busted, like you said. So I downloaded and tried the version that is used for seeding GameTrove and CNET, and it worked great. All of the other sites were seeded from FileFront, so of course they were all corrupted by its original corruption.
I've now made the GameTrove link the #1 download location on our mirrors list for now, and am uploading a new version (that hopefully won't get corrupted) to FileFront. I'll have to talk to them and see what the deal is, I presume it's some sort of issue with their html-based uploader, I guess we'll see.
Also, Admiral: for your .NET 3.5 installer not working, that issue happens with a minority of users on the web-based .NET 3.5 installer. It's a bug that Microsoft is aware of, but they have not put out a fix to my knowledge in the year or so that they have known about it.
The solution, as you mention, is to download the full deal and install that instead.