PHP allows you to set your own exception/error handler with the set_exception_handler and set_error_handler functions. Like most PHP functions that take callbacks as parameters, PHP allows you to pass in an array containing an object name and a method name, e.g.
set_error_handler(array('SomeClass?', 'someMethod'));
This will call the static function SomeClass::someMethod() whenever an error occurs.
However, eAccelerator sometimes fails to handle this correctly. The symptoms are errors like "Cannot find class 'SomeClass?'" occuring in seemingly bogus places, for example whenever a "var $foo;" is encountered in a class definition. This indicates that the "var $foo;" triggered an E_STRICT error (as it should), but the error handler was not found (even though SomeClass? has definitely been defined). If eAccelerator is disabled, the code works fine.
I could not reproduce this bug using a minimal example (otherwise I would have submitted it along with this report).