Apparently Zend Lucene suffers from troubles on 64 bit machines, several bugs ( Exception opening index on 64bit platforms, Lucene doesn’t work on 64-bit). Thats the bad news! The good news is that those bugs can be easily be fixed, the solution is here....
If you want to realize a fulltext search engine you can’t ignore Apache Lucene and its port for Java. This powerful implementation uses a reverse index, like google does, and its results are pretty good. Unfortuantely most webhoster won’t support Java therefore you could switch to the PHP port of lucene implemented by the PHP framework Zend, called Zend Lucene. Thankworthy both implementations are compatible, you just have to consider the right version....