C Sharp Patterns In Action 4.5 Solution Errors

I'm have issues running the solution. Specifically I'm receiving the following errors:

-The name 'Web Security' does not exist in the current context
-Metadata file bin\debug\ActionService.dll could not be found
-The type or namespace 'WebMatrix' could not be found

I've attached a screenshot for the errors also.

I've created a SQL Server database and populated it using the Action.sql file and also updated the app.config file.

Please help.

Fixed it by delete the .suo file and re-opening.

Also... added references to projects requiring WebMatrix via nuget.