--- jquery_ui.install	2010-04-02 15:19:54.000000000 +0100
+++ jquery_ui.install	2010-08-11 17:54:01.000000000 +0100
@@ -34,8 +34,9 @@ function jquery_ui_requirements($phase) 
     $requirements['jquery_ui']['description'] = $t('The <a href="@jqueryui">jQuery UI</a> plugin is missing. <a href="@download">Download</a> and extract it to your <em>jquery_ui</em> module directory. See <a href="@readme">README.txt</a> for more info.', array(
       '@jqueryui' => 'http://jqueryui.com',
       '@download' => 'http://code.google.com/p/jquery-ui/downloads/list?q=1.6',
-      // drupal_get_path() breaks install profiles.
-      '@readme' => dirname(str_replace(getcwd(), '', __FILE__)) . '/README.txt',
+      // drupal_get_path() breaks install profiles, so get the full path from __FILE__
+      // by removing the current directory, then adding the base_url.
+      '@readme' => $GLOBALS['base_url'] . dirname(str_replace(getcwd(), '', __FILE__)) . '/README.txt',
     ));
     $requirements['jquery_ui']['severity'] = REQUIREMENT_ERROR;
   }