The Microsoft support page has a number of potential solution for Windows Installer errors: http://support.microsoft.com/kb/2642495
You could also try this fix:
1. Go to a Windows Vista (Any Version) computer that has the Windows
Installer service running correctly and run regedit (Start-Run-Regedit).
2. Go to the location
HKEYLOCALMACHINE\SYSTEM\CurrentControlSet\Services\msiserver
3. Right click on this key and select "Export" and save the key to a Flash
Drive or any other location.
4. Run sfc/scannow on the damaged Vista computer - you won't need the
install disk as it goes to backup files on your HD. Do not reboot when
complete.
5. Double click the saved .reg file from working machine and import registry
settings to damaged Vista computer.
6. Now reboot and try to install/uninstall.
