|1719 - The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed...|
It might be worth using the "services applet" to check the "Windows Installer" service (MSIServer). If its not started (OK either way) then see if you can start it yourself (you should be able to and it will typically stop itself after 10 minutes or so).
I have seen it mentioned that you can get this error installing via an RDP session and if you wish to do this then open your terminal services connection using the command "mstsc /console".
Perhaps a verbose log will tell you more.
See "KB315346" for details on repairing Windows Installer.