I had tried to install Aleph under 2.6.1 and had the same problem I ran into today, so I know this isn't a result of the upgrade. When I tried to activate El-Aleph, I got a message in a yellow box saying "This plugin cannot be activated as it triggered a fatal error" and gave the following info about the error:
Fatal error: Cannot redeclare aleph_initialize() (previously declared in /thunderhaven.net/wp-content/plugins/el-aleph/aleph.php:37) in /thunderhaven.net/wp-content/plugins/el-aleph/aleph.php on line 49
I've not worked much with php. In general, I can make some minor changes, or do moderate-difficulty things if I have *really* good instructions, just so you know. Any idea what's causing this or how I could fix it?