Create an exact replica/dump on local pc

Hi,
I have a running wordpress site . Now I want to make a dump of the sites to run on my local pc . For this, I did copied all files from remote server to local server folder and copied the db as well. However, when i try to run it, its showing some error like as follows:

Fatal error: Call to undefined function wp() in E:\xampp\htdocs\codesamplez\wp-blog-header.php on line 14

Can anyone know, why this might happen and is there anything else i should do besides changing the database settings.

Regards