Can't load Search API Solr config file

I'm trying to set-up Solr on my local environment. But I can't load the config file.

Set-Up

Ubuntu Server 12.04
LEMP Stack
Tomcat 7
Apache Solr 4.5.1

I installed Solr following the instructions here: http://www.lullabot.com/blog/article/installing-solr-use-drupal.

This means I'm using the apachesolr module config files in both:

/usr/local/src/tomcat/solr/conf
/usr/local/src/tomcat/solr/drupal/conf

This set-ups Solr correctly and allows it run. I can connect to it with Drupal and use the basic index. But if I try to index with it with SearchAPI it will only partially index before throwing an error. (This is the case if I have a bundle filter for a node type. Otherwise it won't index at all.) I get the error:

Error: "Couldn't index items. Check logs for details."

I did a bit of digging and it's because I'm using the wrong config files for search API. So I copied the solr-config files from search API module folder into

/usr/local/src/tomcat/solr/drupal/conf

And gave all permissions to the tomcat user. But on rebooting I get the following Solr error:

drupal: org.apache.solr.common.SolrException:org.apache.solr.common.SolrException: Could not load config file /usr/local/tomcat/solr/drupal/solrconfig.xml

If I put the conf files into

/usr/local/src/tomcat/solr/drupal then I get the "Couldn't Index Items Error".

Could there be something wrong with the config files?