aMember v3.1.6 changed some internal processing that affects the rebuild db process this means that the previous v1.0.x versions now do not work. An update is available on the JLogica web site http://jlogica.com/jess/?act=product&id=8 apart from aMember v3.1.6 compatibility you are also now able to set the 'chunk' size for the number of records processed on each loop. The rebuild also now runs as a plugin, so the existing standard rebuild remains in place after installing make sure to re-load the aMember control panel and you will see a 'Rebuild DB" option under a new menu item 'JLogica'.