CakePHP 1.2 & debug 0

Hmm... I got a real problem, and don't see decision.

PHP4, MySQL, all directory is writeable.

1.1 CakePHP (empty, only framework). Set debug 0 - no problem. I see normal "Hello page of CakePHP"

1.2 CakePHP (empty, only framework). Set debug 0 - and get blank page... No data. No one byte.
In choise debug 1 - I see "Hellopage", when switch to debug 0 - blank.

Where is error? I don't understand... No one string of code... Where is bug???