[fw-formats] Zend_Search_Lucene throws fatal error

Hi,

I just checked the example 38.2.1. in the manual:

http://framework.zend.com/manual/en/zend.search.lucene.index-creation.html

When I test this example I get an error with ZF 1.6.2:

Fatal error: Exception thrown without a stack frame in Unknown
on line 0

When I add the line

$index->commit();

at the end of the script, then the fatal error does not occur anymore.
Does the manual need to be updated or is there a bug in Lucene?

Thanks and best regards,

Ralf