Complete
To be used with care. Pages are complete only when they meet the posting guidelines.
Everyone else has figured this out by now, but loudly proclaiming ignorance (as soon as I know I am ignorant) is a proud U.S. of A. tradition (albeit ordinarily done with less self-awareness).
Apologies if you had to click to read this, because the whole insight is in the page title: Use hook_theme for new theming functions and templates; use hook_theme_registry_alter to take over existing ones.
Agaric will demonstrate this with a negative example and a positive example.
I received an error because the schema for member module wasn't loading. After visiting the modules page all was fine.
Update for D7:
drupal_flush_all_caches();
drupal_flush_all_caches() should work for just about anything. registry_rebuild() alone did not work in my tests.
Drupal 6
The Drupal function to reset the theme registry is drupal_rebuild_theme_registry (D6).
You can add it to your template.php while developing:
Agaric wanted and now has happily found a way to submit a node and get the create new content form immediately.
And there is a module to do that:
http://drupal.org/project/submit_more
(I recall I wanted it as a button to "save and add new" – I still think that would be a superior user interface.)
For Drupal core development in Git rather than CVS, git://github.com/mikl/drupal.git is updated every hour from Drupal.org's CVS.
Resolution
If, like Agaric, you're moving from multisite to separate installations for each site (or vice versa) you may find your user-uploaded file paths changing. Drag.
The solution is updating your database, and you can replace part of the file path with straight SQL:
UPDATE files
SET filepath
= REPLACE(filepath
, "sites/help4computers.com/files/", "sites/default/files/")