Error during deployment

•  Error :  "Entity is not org-accessible" error while deployment or saving the classes.

          Cause of the error - You have written a code that share a record and sharing model is not set to  private.

          Solution :  set sharing model to private for the object you are applying sharing rule in your code.
Security control -.> Sharing Settings -> select object -> Set OWD private

•  Error : APEX deploy fails "Package Version number does not exist" while saving the classes and pages.

          Cause : Classes are dependent on installed package. Your org has lower package version installed and the classes you want to deploy are in higher package version.

You can check your installed package version in your org:
App Setup -> Installed Packages_>click on your package ->see the Version Number

Package version of the class can be checked by version setting or by metadata file in eclipse.

Solution : 1. Upgrade the package of your org.
                 2. Try setting your project to work offline.Edit the metadata file and remove the dependencies on the manage package, then deploy straight to the target org.

Go to your project in eclips -> force.com -> work offline -> remove the dependancy of your classes and pages on package then deploy to server.