I want my Drupal 7 theme to use a custom block.tpl.php for my navigation bar (Defined: regions[navigation] = Navigation bar). So I copied block.tpl.php from the block module to my theme directory and tried to give it different names (following different guides on the web). None of them seemed to work. Then I wanted to make sure it was a naming problem so I changed the name back to block.tpl.php and changed its contents (removed the h2-tag for the title). I reloaded my site but nothing happened so there must be another problem.
Any ideas on how to fix this?