[Plugin: wpSearchMu] Updated to 3.1 now it's all broken

I’m getting all sorts of errors when I try to update a page, make a post or even shut this plug-in off.

So frustrating.
Fatal error: Uncaught exception 'Zend_Search_Lucene_Exception' with message 'File '/var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/data/1/segments_xr' is not readable.' in /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene/Storage/File/Filesystem.php:59 Stack trace: #0 /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene/Storage/Directory/Filesystem.php(359): Zend_Search_Lucene_Storage_File_Filesystem->__construct('/var/www/public...') #1 /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene.php(323): Zend_Search_Lucene_Storage_Directory_Filesystem->getFileObject('segments_xr') #2 /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene.php(460): Zend_Search_Lucene->_readSegmentsFile() #3 /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene.php(186): Zend_Search_Lucene->__construct('/var/www/publi in /var/www/public_html/2011.empowermm.com/wp-content/mu-plugins/wp-search-mu/Zend/Search/Lucene/Storage/File/Filesystem.php on line 59