If existing tables are found, install dies with Call to undefined function file_directory_path()

Existing issues at http://drupal.org/node/102599 and http://drupal.org/node/100476 deal with this same error message but for different reasons.

I can successfully reproduce this error when I try to install Drupal on an existing database using the same prefix as an existing installation. In other words, if Drupal tries to create a table that already exists, you get "Call to undefined function file_directory_path()" which is not the best first impression of Drupal. There should be an accurate error message saying something like, "Table whatever already exists. Please choose another prefix or database."