In some cases when you install packages you might receive an error, stating
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2869

This happens because UAC(User Account Control) in Vista denies execution of some MSI Custom Actions that interact with the system and require administrative privileges.
1. Run Command Prompt as administrator
2. Locate installation file using cd and dir commands. For instance, to get to your Desktop, try typing cd /d "%USERPROFILE%\Desktop"
3. Launch installation file using msiexec /i SetupFile.msi command, where SetupFile is the name of your setup file that causes error.
This launches installation with administrative privileges and therefore fixes the problem.