Getting error when uploading file

This was working when I had my upload directory in my app folder.
I now what to upload to the server folder called media/categories

The config below is showing:
The upload path does not appear to be valid.

Code:

$config['upload_path'] = '/media/categories/';

Thank you

[EDIT]
It works if I hard code the path:
'/lamp/www/media/store_categories'

How can I do this so it works when I deploy the app?

Try it without leading slash.

if your directory architecture is like :
- system
- application :
  -- dir_upload
  -- application_name :
      --- config
      --- controller
      --- models
      --- helper
      --- view

If you want to upload files and record its in directory name 'dir1_upload', path will be 'dir_upload/'.
Use constants APPATH for other configuration or define it as well.
Think to check read/write attributes for your directory too (chmod).

The code you posted shows /media/categories/, but you say it works when you hard code it to /lamp/www/media/store_categories (store_categories)

Try
FCPATH . 'media/store_categories';

FCPATH is the full path to your index.php file, which is in the root of your site. So the above should equate to /lamp/www/media/store_categories like you hardcoded it

The code you posted shows /media/categories/, but you say it works when you hard code it to /lamp/www/media/store_categories (store_categories)

Try
FCPATH . 'media/store_categories';

FCPATH is the full path to your index.php file, which is in the root of your site. So the above should equate to /lamp/www/media/store_categories like you hardcoded it

Thank you, that resolved my issue.