I installed it, and checked it out in Packageview. Apparently it only installed libfacebook.so in /usr/lib/purple-2/ and some docs/icons, nothing more. No manager or profile stuff.

Now, I have both 1.63 and 1.64 versions in /usr/lib/purple-2/. Since I nowhere in the config files tell it which one to use, I don't know which version it is using now. Anyway, I doubt that it matter regarding the merging problem, but I'll move 1.64 out of there and see if it makes any difference.