We’ve recently faced the following error while using Lucene indexes with Symfony:
Fatal error: Ignoring exception from Zend_Search_Lucene_Proxy::__destruct() while an exception is already active
Sounded scary and some quick googling showed that the problem is serious:
http://framework.zend.com/issues/browse/ZF-1471
http://stackoverflow.com/questions/797570/zend-search-lucene-crashes-during-indexing
but eventually it turned out that it was enough to chmod 755 indexes folders to allow Zend writing there.