When installing VistaDB (either a new installation or an update) the installation may proceed rapidly to near the end and then appear to hang. Looking at the UI it may say that it's writing INI files. If left alone, the install eventually completes
During the final phase of the installation VistaDB installs its extensions into Visual Studio. This is done once for each version of Visual Studio detected on the local system that is supported by VistaDB (currently Visual Studio 2010, 2012, and 2013). Depending on the number of other extensions already installed and other factors it may take a while to install in each version of Visual Studio. If the Visual Studio integrated help system is installed locally then the VistaDB help is added to it as well.
Wait until the installation completes. If it appears genuinely hung for a long time check for modal dialogs that may be hidden behind another window. This can happen if another Visual Studio extension displays a dialog when Visual Studio is run in installation mode.