When i installed Zend Framework first i copied the wrong folder and got some Zend related errors too.
If you unpack the Zend Framework there is a folder library in there is a folder called Zend. Just copy this to the root of your LetoDMS installation, Lucene should find and use it.
If you unpack the Zend Framework there is a folder library in there is a folder called Zend. Just copy this to the root of your LetoDMS installation, Lucene should find and use it.