You may encounter this error on Windows Vista machines. To correct it, log in as an administrator and perform the following actions:
Click Start
Type "Run" in the search box without the quotes
Click Run in the resulting application list
type "gpedit.msc" without the quotes
Press OK
Select Local Computer Policy > Computer Configuration > Administrator Templates > Windows Components > Windows Installer
Right Click "Disable Windows Installer" from the list of options in the right hand pane
Select Properties from the context menu
In the resulting window, ensure that "Not Configured" or "Disabled" is selected.
Click OK and close the group policy object editor
Run the installer again (you may need to restart your computer first). The installer should now work.
See if this helps :)