Doctrine Compiler recursively includes all the files it finds under Doctrine::getPath() location, which is the directory that contains Doctrine.php. In some cases it is convenient to put other libraries in the same directory, especially if they also use Zend Framework-like naming scheme. If including any of those files fails, for example because of parse error or not satisified dependency, to whole compilation fails.
The fix changes the directory traversed recursively to Doctrine::getPath().'/Doctrine', so the compiler does not try to include anything unrelated.