After installing Ad Flash 2.6, the update.php gives errors

There was an error when running the update.php after installing the 2.6 update from 2.4. Here are the errors:

* warning: Invalid argument supplied for foreach() in /usr/local/apache2/vhosts/mysite.com/htdocs/includes/database.mysql-common.inc on line 109.
* user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 query: ALTER TABLE ad_flash ADD PRIMARY KEY () in /usr/local/apache2/vhosts/mysite.com/htdocs/includes/database.mysql-common.inc on line 374.
* warning: Invalid argument supplied for foreach() in /usr/local/apache2/vhosts/mysite.com/htdocs/includes/database.mysql-common.inc on line 109.
* user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 query: ALTER TABLE ad_flash ADD INDEX aid () in /usr/local/apache2/vhosts/mysite.com/htdocs/includes/database.mysql-common.inc on line 434.

The following queries were executed:
ad_flash module
Update #6000
    * ALTER TABLE {ad_flash} DROP KEY aid
    * Failed: ALTER TABLE {ad_flash} ADD PRIMARY KEY ()
    * Failed: ALTER TABLE {ad_flash} ADD INDEX aid ()

Ads seem to still be displaying and functioning correctly afterward. Are these errors to be worried about? Why did they occur?