CRM web app error

I have created an MVC app to download pdf for  custom entity, this app working fine on my local machine, but when i host this app on CRM server i am getting this 

Could not load file or assembly 'Microsoft.Crm, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.