PHP require/include and relative path error

It is little difficult to get the right path in PHP sometime. PHP gets the path based on top page. To get the right path two functions are very useful - getcwd() and realpath().
To get what PHP is understanding of your supplied path for require/include, use realpath(). It will give you the path PHP has expanded to use. If PHP translated path is not correct then it will return bool(false).
Use this code

var_dump(realpath('your path'));

to see the Boolean value. If path is correct then it will return the real path.

To know where are you right now, you can use getcwd().

echo getcwd();

It will return the current execution path of php script. You need to consider this path when writing the relative path for include/require. Write your path related to this provided path.