Hello G S S,
In which folder did you install OpenAccess, you have to replace
C:\Program Files\Telerik\OpenAccess ORM by this folder. If you say you cannot find the file on your drive there must be a mistake. Maybe you clicked OK if VS comes up with the error and the file has been renamed in the same directory, please open the dirictory and double check.
If you say you went through the document step by step did you check that all settings are correct. Our Addin cannot work if not all 3 mentioned things are set accordingly.
the Telerik team