Hi Kamal,

The two most common causes for this problem are:

1. Missing administrative rights when installing Visual WebGui - Make sure you "Install as Administrator". It is not enough in some cases to log in using an administrator account, you have to make sure you have full administrative rights.
2. Missing Web Developer from Visual Studio installation - This I imagine is not the case for you, as you were using Visual WebGui just a while ago. Unless you have made changes to your Visual Studio installation and in that case, please see here.

Hope this helps,

Palli

Hi Kamal189,

Can you explain further what exact steps you take when you say you want to open an interface ?

Normally, in Visual WebGui, you create forms or usercontrols and drop the controls from the toolbar to the design area of those. You can create inherited forms and usercontrols and you can implement an interface on either of them, but in order to drag your controls from the toolbar and drop them onto the designer area, you need to use Form or UserControl or derivatives.

In case you have not already, I suggest you view the getting started videos and articles here, one of which will show you how to create a Visual WebGui application.

Hope this helps,

Palli