the type or namespace name "resource' does not exis

Hi,

I'm having trouble adding the custom Folder widget FlashSlider  ?

But i have followed this tutorial.

Install the control in the Settings as follows: 

a) In the sitefinity back-end navigate Administration -> Settings ->Advanced 
b) choose Toolboxes -> Page Controls -> ContentToolboxSection 
c) Add a new widget of type "~/Widgets/YourControl/YourControlName.ascx"

Can you help me solve the problem...???

I'm trying to edit sitefinitywebapp on visual studio 2015