error installing version 2.1

Hello,

Error  1  It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level.  This error can be caused by a virtual directory not being configured as an application in IIS.  C:\n.c.c.2.1\Presentation\Nop.Web\Web.config  73  

regards,

Error is self-descriptive. Configure virtual directory as an application in IIS (try to google, there're a lot of articles about it).

yeah that's right