Próbuj:
require_once( IPSLib::getAppDir( 'forums' ) . '/app_class_forums.php' );
$appClass = new app_class_forums( ipsRegistry::instance() );
require_once( IPSLib::getAppDir( 'forums' ) . '/sources/classes/post/classPost.php' );
$this->_postClass = new classPost( ipsRegistry::instance() );
$this->_postClass->setIsPreview( false );
$this->_postClass->setForumData( ipsRegistry::getClass('class_forums')->forum_by_id[ 5 ] );
$this->_postClass->setForumID( 5 );
$this->_postClass->setAuthor( 1 );
$this->_postClass->setPublished( true );
$this->_postClass->setSettings( array( 'enableSignature' => 1,
'enableEmoticons' => 1,
'post_htmlstatus' => 0,
'enableTracker' => 0 ) );
$this->_postClass->setPostContent( "testowanko" );
$this->_postClass->setTopicID( 1273 );
$topic = $this->registry->DB()->buildAndFetch( array( 'select' => '*', 'from' => 'topics', 'where' => 'tid=1273' ) );
$this->_postClass->setTopicData( $topic );
$this->_postClass->addReply();