If you would like to upgrade from the original b2/Cafelog (versions 0.5.x up to 0.6.2), please follow these steps:
Do not install the current version of b2evolution right now. Instead, download b2evolution version 1.x. You can download almost any version of b2evolution here.
Follow the instructions incuded in b2evolution 1.x to upgrade from b2/Cafelog.