Base table or view not found when upgrading from 6.x to 7.x

I'm upgrading a site with Drupal 6 to Drupal 7.
When I try to upgrade ad module from 6.x to 7.x, I have the following errors:

PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'ad_type' doesn't exist: SELECT * FROM {ad_type}; Array ( ) in ad_types() (line 233 of /var/www/siete_expreso/sites/all/modules/ad/ad.module).

And the site fails: "Error
The website encountered an unexpected error. Please try again later. "

What I can do?