Zend Optimizer not running on self compiled PHP

Hi everybody, on an exotic HW (composition) I had to go on Linux Fedora Core 14. I compiled Apache 2.2.17 and PHP 5.2.14 manually from the sources. Everything went well except the Zend Optimizer (as always). I tried 3.3.3 and 3.3.4 and 3.3.9
With no success. I just can’t get it to work. I can find no really error-messages in the apache logs. Anybody who has seen the same ?
Any ideas of workarounds ?
Uwe

do you have xdebug extension running? if yes, try to disable it.

Not that I know. I searched the php.ini and didn’t see a hint. Any other ideas ?