Missing database table after clean 6.x.2 install

I've just installed Embedded Media Field for the first time on a new Drupal site.

Using drush, I downloaded the package

$ drush dl emfield media_youtube

In my custom module I activate the modules I need (this is going on a production site, so due to internal workflow, all interaction with the database is through PHP code in our module.install file)

  module_enable(array('emfield', 'emvideo', 'media_youtube'));

The settings for YouTube seem to be fine out of the box, so with an embedded video field on a CCK content type, I add a YouTube URL to an existing node.

The video saves, and displays correctly on the page, but I get this (spurious?) error:

    * user warning: Table 'italyrc.cache_emfield_xml' doesn't exist query: SELECT data, created, headers, expire, serialized FROM cache_emfield_xml WHERE cid = 'emfield:request-header:http://youtube.com/v/FJLyTNuYP_k?fs=1' in /home/aaron/sites/italianresidenceclubs.com/includes/cache.inc on line 26.
    * user warning: Table 'italyrc.cache_emfield_xml' doesn't exist query: UPDATE cache_emfield_xml SET data = 'O:8:\"stdClass\":8:{s:7:\"request\";s:102:\"HEAD /v/FJLyTNuYP_k?fs=1 HTTP/1.0\r\nHost: www.youtube.com\r\nUser-Agent: Drupal (+http://drupal.org/)\r\n\r\n\";s:4:\"data\";s:0:\"\";s:8:\"protocol\";s:8:\"HTTP/1.0\";s:14:\"status_message\";s:2:\"OK\";s:7:\"headers\";a:8:{s:4:\"Date\";s:29:\"Mon, 11 Oct 2010 13:00:19 GMT\";s:6:\"Server\";s:6:\"Apache\";s:22:\"X-Content-Type-Options\";s:7:\"nosniff\";s:10:\"Set-Cookie\";s:197:\"VISITOR_INFO1_LIVE=Adaylh82DxU; path=/; domain=.youtube.com; expires=Wed, 08-Jun-2011 13:00:19 GMT,VISITOR_INFO1_LIVE=Adaylh82DxU; path=/; domain=.youtube.com; expires=Wed, 08-Jun-2011 13:00:19 GMT\";s:7:\"Expires\";s:29:\"Tue, 27 Apr 1971 19:44:06 EST\";s:13:\"Cache-Control\";s:8:\"no-cache\";s:14:\"Content-Length\";s:4:\"1005\";s:12:\"Content-Type\";s:29:\"application/x-shockwave-flash\";}s:4:\"code\";s:3:\"200\";s:13:\"redirect_code\";s:3:\"200\";s:12:\"redirect_url\";s:41:\"http://www.youtube.com/v/FJLyTNuYP_k?fs=1\";}', created = 1286802019, expire = 1286805619, headers = '', serialized = 1 WHERE cid = 'emfield:request-header:http://youtube.com/v/FJLyTNuYP_k?fs=1' in /home/aaron/sites/italianresidenceclubs.com/includes/cache.inc on line 109.