The following causes are possible.

1) Yamaha has confirmed that VOCALOID products cannot be installed if Kensington mouse drivers are installed.

-> Uninstall the Kensington mouse driver, install the VOCALOID product, and then reinstall the mouse driver.


2) If the system's temporary folder is set to a location other than a local drive, such as a RAM disk, the installer might not run correctly because the installer tool requires that the temporary folder be set to a local drive.

-> Set the temporary folder to a local drive (such as the C drive).


3) If you do not have the required authorities to run the installer, in some environments the installer might not run correctly.

-> If this occurs, use administrator authority to run the installer, and then proceed with setup normally.


Note that even though error codes will vary depending on the product being installed, error codes that end with (0) are the same as above.

Also, if the problem is not resolved after attempting solutions 1) through 3) above, try using the "Troubleshooting Tool for Installing/Uninstalling Programs" at the following URL:
http://support.microsoft.com/kb/2438651/ja