[MCL-3287] "unknown error" when running Minecraft.msi

Moderator note

This issue may be caused by Antivirus / Firewall / bad Proxy / Parental control software or malware.
Workaround: Use the "old" Launcher:
- Go to https://minecraft.net/download
- Klick on Show all platforms
- Follow the instructions:
  
  Minecraft for Windows (alternative)
  
  If you have issues with the new Windows download, you can try the old one by downloading Minecraft.exe. If given the option, save the file instead of running it. Save the file anywhere you'd like, then double-click the program to run. This does require Java to be installed, however.
- Download the latest Java version from http://www.java.com/en/download/. (When using a 32-bit browser on a 64-bit operating system the automatic version detection will only show the 32-bit version of Java, the 64-bit version needs to be downloaded manually: http://www.java.com/en/download/manual.jsp )

just installed minecraft and before the launcher popes up it claims there is an unknown error. this error apparently comes from the mine craft launcher as that is what the program is called in the bar. please help

current version of 19/12/2014

From ~~MCL-3337~~

Native Launcher Version: 4
Operating System: Windows Vista SP2
Application Hash: 527b44fc451b127eee56b88f79d9aeafb65ebda9
Java Version: 
x64: 1
Starting download of: https://launchermeta.mojang.com/mc/launcher.json
Starting download of: https://launchermeta.mojang.com/mc/launcher.json
Starting download of: https://launchermeta.mojang.com/mc/launcher.json
Failed to download manifest
Failed to start application .\runtime\jre-x64\\bin\java.exe -cp "game\launcher.jar" net.minecraft.launcher.Main