
Check the permissions on that directory. Make sure it’s set to at least 755, or maybe 777.
PHP doesn’t parse [(base_url)] when used in a snippet - take a close look at your error msg:
Error: opendir([(base_url)]/assets/files/downloads/icons/) [function.opendir]: failed to open dir:
In a snippet, use something like:
$dir = $modx->config[’base_path’] . ’/assets/files/downloads/icons/’;
if ( !preg_match('/\.thumb*/',$file) && $file != '.' && $file != '..' && $is_image )