In the process of setting up Thunderbird - a Google search actually led me pretty quickly to the tutorial on your site. :)

I'm using OSX 10.5.8 with Socialite 1.0.2 on a MacBook 2,1. In the Socialite support forum I saw that I'm not the only one with the crash issue and that they haven't fixed it yet because they weren't able to replicate the error. (It did get rarer when I switched from Mail.app to Mailplane, but it still happened and I don't want to ruin my laptop.) :/