Install file doesn't have the squiggly brackets for ad_groups

This line:

db_query("INSERT INTO ad_groups (gid,name, description) VALUES(1, 'default', 'All new advertisements will be added to this default group until you create your own custom advertisement groups.')");

should be

db_query("INSERT INTO {ad_groups} (gid,name, description) VALUES(1, 'default', 'All new advertisements will be added to this default group until you create your own custom advertisement groups.')");