Botched my site upgrade
Switch to a stock D7 theme - clearing the cache is not enough if there's a bug in your theme as the buggy code is still going to reload.


Either use drush (highly recommended) to change your default theme to another, or...
Use the techniques mentioned here (should apply to D7): http://drupal.org/node/200774 or...
Rollback to your D6 code/database, disable the borked theme, and then retry the upgrade.