Windows Installer Error - This installation package could not be opened. Verify the package exists and that you can access it.

This is a Windows error and indicates a problem with either:

- The downloaded file
- You are not logged in with administrator rights
- The Windows Installer itself
- Corrupted system files

The first thing to try is to delete the file you have already downloaded and download the file again. If you chose to 'Run' the file then clear out all temporary files before you do this (Ctrl+Shift+Del).

If the above does not work then follow these steps and try to install after each step.

Step 1:
Try to ensure that Windows Installer service is running.
Go to Start and click on Control Panel.
Go to Administrative Tools.
Click on Services and scroll to Windows Installer.
Double click to bring up the service.
Check to see if the startup type is set to Manual.
Service status is usually stopped. Try and start the Windows Installer service.

Step 2:
Click Start, and in the start search box, type cmd.
Then right click and select, ‘Run as Administrator’.
At the command prompt, type:
- Type msiexec.exe /unregister, and then press ENTER.
- Type msiexec.exe /regserver, and then press ENTER.


Step 3:
If that doesn't help, then let's run System File checker to see if you have any corrupted system files.
Click Start
Type: CMD, from the results, right click CMD
Click 'Run as Administrator'.
At the Command Prompt, type: sfc /scannow
This will check for any integrity violations and fix any corrupted operating system files.
Restart your system.

Finally, Microsoft have a live fix page for this. You could try that here - http://support.microsoft.com/kb/2438651