I recently saw a thread about a guy who had trouble installing from the msi, but eventually got it to work. I was going to post in that thread but I figured that this needs its own thread for people with the same problem.

Requirements:
Winrar (Trial or bought, doesn't matter)
The AoS installation file (aos054install.msi)

Install Winrar. If you already did then go ahead and open the .msi file with it (Right click>Open with>Winrar)

You should see all the necessary game files, but without folders. Set up your Ace of Spades folder (C:\Ace of Spades, or where ever), and begin creating new folders (kv6, wav, png, vxl), and move the corresponding files there, from the msi. The files voxed, client, server, config.cfg, changelog.txt, voxedhlp.txt, and readme.txt are moved to the root folder (C:\Ace of Spades).

Now you're all set.