Hey Mike,
You need to place the tables from the drupal database in the joomla database
In joomla we normally have this #__content the #__ is the prefix and it is normally replaced by a string such as jos_content, mvp_content etc. This prefix is dynamic - it's different for most installation (unless you specify a standard prefix yourself).
On most drupal installations there is no prefix. So the tables are just node, node_relations etc. But on some installations we have lvc_node, lvc_relations or whatever the user decided to enter.
We need to know this prefix and you need to have the drupal tables in the same joomla database.
Regards,
Daniel