Whilst a CodeName or DisplayName field are not required it can be advantageous to have these since Kentico will then take care of additional functionality. In your case you should consider CompanyName for the display name, however, you probably would not need a codename.
The error you are getting indicates that the object is configured with a code name. On the code tab confirm that the code name field shows '(none)', then click the Generate Code button. After that copy and paste the code for the Info and Provider classes to the relevant files in your application (varies depending on whether it is a web app project or a web site project).
I would also suggest you read the docs on developing custom modules and in particular the section on configuring the Info class so that you understand how they should be configured (note: in particular the code generation does not include any Parent object type or parent id which needs to be manually added).