We believe that this happens if you double-click on the VisIt icon on the Windows desktop due to the VisIt start up directory being set to VisIt's data directory in the desktop shortcut. The VisIt installation program for Windows has been changed as of version 1.5 so that the start up directory is set to the directory in which VisIt was installed. This allows Windows to more easily find VisIt's dynamic-link libraries when trying to launch the viewer component. You can work around the problem by using the VisIt menu option in the start menu, by running VisIt from the Windows command prompt, or by editing the properties for the desktop shortcut so the start up directory for VisIt matches the location where VisIt was installed. If you try these solutions and the problem persists then it is possible that your computer has misconfigured network options or there is another program interfering with VisIt's launch (e.g. firewall, virus checker).