and added a echo 'constructor'; in the eZDebug constructor, to see if it was called: it was called, the error *disappeared* and - even cooler - after undoing all my changes, it didn't come back!!
The next error was behaving all the same (eZDir) and so the errors would continue.
After four years of PHP development, such behaviour is really new to me!
I think you should win a prize trying to set up ez publish on such low-end hardware given all the layers that need to be processed before a page arrives at your browser ;-)