What could be causing drupal to want to reinstall itself after I clear cache?
That occurs because Drupal can't connect to its database

Ensure you have:


settings.php


in your Drupal /sites/default folder.

settings.php must be readable by the webserver user and contain valid database connection string credentials for that server. Make sure the base_url is either default commented out or valid for that domain.

See _drupal_bootstrap_database for the place where the install.php redirect occurs.

Also, make sure you've run update.php and do clear all caches if possible.