Yii failed to connect to postgresql database in slackware 13.37 - postgresql

Question

I trying an application made in Yii 1.1.14 in slackware 13.37
When trying to connect it shows a pagae with this message:
Error 500
CDbConnection failed to open the DB connection.
The application.log in protected/runtime shows this
2017/09/07 10:32:16 [error] [exception.CDbException] could not find driver
2017/09/07 10:32:16 [error] [exception.CDbException] exception 'CDbException' with message 'CDbConnection failed to open the DB connection.' in /var/www/htdocs/myapp/yii/framework/db/CDbConnection.php:388
Stack trace:
#0 /var/www/htdocs/myapp/yii/framework/db/CDbConnection.php(330): CDbConnection->open()
#1 /var/www/htdocs/myapp/yii/framework/db/CDbConnection.php(308): CDbConnection->setActive(true)
#2 /var/www/htdocs/myapp/yii/framework/base/CModule.php(387): CDbConnection->init()
#3 /var/www/htdocs/myapp/yii/framework/base/CApplication.php(450): CModule->getComponent('db')
#4 /var/www/htdocs/myapp/yii/framework/db/ar/CActiveRecord.php(634): CApplication->getDb()
#5 /var/www/htdocs/myapp/yii/framework/db/ar/CActiveRecord.php(667): CActiveRecord->getDbConnection()
#6 /var/www/htdocs/myapp/yii/framework/db/ar/CActiveRecord.php(1455): CActiveRecord->getCommandBuilder()
#7 /var/www/htdocs/myapp/protected/components/UserIdentity.php(8): CActiveRecord->find('LOWER(username)...', Array)
#8 /var/www/htdocs/myapp/protected/models/LoginForm.php(52): UserIdentity->authenticate()
#9 /var/www/htdocs/myapp/yii/framework/validators/CInlineValidator.php(42): LoginForm->authenticate('password', Array)
#10 /var/www/htdocs/myapp/yii/framework/validators/CValidator.php(213): CInlineValidator->validateAttribute(Object(LoginForm), 'password')
#11 /var/www/htdocs/myapp/yii/framework/base/CModel.php(159): CValidator->validate(Object(LoginForm), NULL)
#12 /var/www/htdocs/myapp/protected/controllers/SiteController.php(97): CModel->validate()
#13 /var/www/htdocs/myapp/yii/framework/web/actions/CInlineAction.php(49): SiteController->actionLogin()
#14 /var/www/htdocs/myapp/yii/framework/web/CController.php(308): CInlineAction->runWithParams(Array)
#15 /var/www/htdocs/myapp/yii/framework/web/CController.php(286): CController->runAction(Object(CInlineAction))
#16 /var/www/htdocs/myapp/yii/framework/web/CController.php(265): CController->runActionWithFilters(Object(CInlineAction), Array)
#17 /var/www/htdocs/myapp/yii/framework/web/CWebApplication.php(282): CController->run('login')
#18 /var/www/htdocs/myapp/yii/framework/web/CWebApplication.php(141): CWebApplication->runController('site/login')
#19 /var/www/htdocs/myapp/yii/framework/base/CApplication.php(180): CWebApplication->processRequest()
#20 /var/www/htdocs/myapp/index.php(14): CApplication->run()
#21 {main}
REQUEST_URI=/myapp/index.php?r=site/login
HTTP_REFERER=http://192.168.0.131/myapp/index.php?r=site/login
The source code of the application and its connection to the database works fine in debian and ubuntu.
Others applications made in php can can connect with the same database in the slackware server.
any help?