I am using Drupal 7 and I installed the module Simplenews to send newsletters. I put the file in sites/all/modules in my Drupal installation (local) and I activated the module. The content type Simplenews newsletter appeared so all seemed fine. But when I tried to send a test newsletter, I ran into the following error:
User warning: The following theme is missing from the file system: sites/all/modules/simplenews. For information about how to fix this, see the documentation page. in _drupal_trigger_error_with_delayed_logging() (line 1156 of C:\applix\UwAmp\www\drupal7\includes\bootstrap.inc).
Unable to send e-mail. Contact the site administrator if the problem persists.
The thing is, I am absolutely sure that sites/all/modules/simplenews exists. In this error message there is a link leading to the following page. It is said that this error occurs when a module has been deleted without uninstalling it first - but I haven't uninstalled any modules - neither simplenews nor one of the others. So where does this come from?
Also, I found the module Missing Message Fixer that aims at fixing that sort of problem. But I am not sure if I should install it since it seems to aim at messed up removals.
Do I need an additional module to send mails in Drupal 7? I only need them for the newsletters.