missing object_cache result in some warnings

Hi, in my vip dev environment I got these after activating batcache following the istructions:

```
Warning: include_once(/srv/wp-content/object-cache.php): failed to open stream: No such file or directory in /srv/wp-content/mu-plugins/batcache/advanced-cache.php on line 355

Warning: include_once(): Failed opening '/srv/wp-content/object-cache.php' for inclusion (include_path='.:/usr/local/php/lib/php') in /srv/wp-content/mu-plugins/batcache/advanced-cache.php on line 355
```

reading advanched-cache.php seems like the absence of object-cache.php triggers a return at the half of the file...
why don't check if file exists before including, to avoid warning?
and why object cache is required for a large portion of the script, but it's not included in the plugin itself?
where can i find and download a stable version of it?