Hi Jerry,
"With sources", as the name implies, is an installation package that include the public sources of the framework, which you can use to take a look at how we do things. To use this type of installation, you have to add a few references to your project.
Knowing next to nothing about your environment, let's start with some basic questions that may help you and will also give me more information on your exact environment:
1) What version and type of Visual Studio are you using (for instance VS2010 Professional).
2) Did you install Visual Web Developer as a part of your Visual Studio installation (you can verify by loading Visual Studio and then go to Help / About and see if you spot Visual Web Developer listed in the Installed Products).
3) What is the exact name of the Visual WebGui .MSI file you are installing?
4) Did you install that file "As Administrator" (login in with administrative privileges is not enough, you may have to "Run as Admin") ?
5) Did you get any warnings when installing (usually seen just before the install starts, as yellow exclamation marks) ?
6) Did you activate your trial, or did you purchase a license and activate it (if using Visual Studio Express, this is not necessary) ?
7) What Gizmox assemblies are referenced in your project ?
Palli