Hello, I would like you to help me. I am running this file but I get an error in the web.config. I am using the visual studio 2013 and I think that earlier I would have done it with the visual studio 2005. The error comes to me like the image I would like Please help me 
The ddl you are looking for vs2013 can not find it. What I would do is ask if the project you are modifying is published on an IIS server. If so, ask if you can obtain the missing dlls, and manually add them to your project. After adding them do not forget to register it in windows.
Greetings
What happens is that the libraries are missing and they are not referenced in the project. In this case CrystalDecisions.Enterprise.Framework.dll (and I guess the rest of CrystalDecisions.*.dll either.
If the application was working somewhere, in the folder bin of it should be (with a little luck). If not, the machine that was executing it will be registered in the assembly record. They can be copied using the command line and looking in the C:\Windows\assembly\GAC_MSIL folder.
Once they are located, copy them into a folder where the solution is and from Visual Studio add a reference directly to those DLLs.
If this does not work, you may have to get the installer for the Crystal Reports DLLs with the specific version (that is, the CCRedist2008_xxx.msi in the image.