http://productforums.google.com/forum/#!topic/chat/3eM48STZR-U

This link above solved the problems of getting google video and voice chat to work

Problems#

1) Uninstallation of google voice and video chat plugin does not work showing some .msi file not available
2) Installation of Google voice and Video Chat plugin does not work showing fatal error : 1603

Clicking on link above posted and installing .msi file from the user MSN Skydrive shared folder, helped me overcome both of the Problems# listed above :) Happy