pear isn"t returning affectedRows

$types =
array('text','text','text','date','text','text','text','inte ger','integer','integer','integer','integer','integer','inte ger','integer','integer','integer','text','text');
$st = $this->mdb2->prepare("INSERT INTO girls
(email,name,surname,dateOfBirth,country,city,nationality,tal l,weight,hairColor,eyeColor,education,profession,maritalStat us,children,smokingHabits,drinkingHabits,aimOfSearch,notes)"
."VALUES
(:email,:name,:surname,:dateOfBirth,:country,:city,:national ity,:tall,:weight,:hair,:eye,:education,:profession,:marital Status,:children,:smokingHabits,:drinkingHabits,:aimOfSearch ,:notes)",
$types);
$data = array('email' => $this->email, 'name' => $this->name, 'surname'
=> $this->surname, 'dateOfBirth' => $this->dateOfBirth,'country' =>
$this->country,'city' => $this->city,'nationality' =>
$this->nationality,'tall' => $this->tall, 'weight' =>
$this->weight,'hair' =>
$hair,'eye'=>$eye,'education'=>$education,'profession'=>$pro fession,'maritalStatus'=>$maritalStatus,'children'=>$this->c hildren,'smokingHabits'=>$smokingHabits,'drinkingHabits'=>$d rinkingHabits,'aimOfSearch'=>$this->aimOfSearch,'notes'=>$th is->notes);
$st=$this->mdb2->prepare("insert into girls(email) values ('d.cz')");
$affectedRows = $st->execute();
if (PEAR::isError($st)) die($st->getMessage());
var_dump($affectedRows);

affectedRows is an object and not int. any idea why?