Plugin’s directory permissions are: drwxr-xr-x
Sorry, I meant that “my-plugin/my-plugin.php” looks like:
<?php
/*
Plugin Name: My Plugin
*/
and “my-plugin/uninstall.php” looks like:
<?php
i.e. there is no PHP comment before <?php, and there is no nested <?php tags. Note also that the closing ?> is optional (and not recommended).
Any other ideas?