What version of Lotus Notes are you running? Do you have any fix packs installed?
The Fix Packs: FP1, FP2 & FP3; for Lotus Notes 8.5.1 disables the use of Facebook Feeds and Posting.
This problem was introduced in FP1, and was meant to be fixed in FP3, but unfortunately it is not.
If you have any of these Fix Packs installed and you wish to use Facebook in WildFire, the only option at this stage is to uninstall them. This can be done by running the same Fix Pack installation file again. As this is not an ideal solution, it is only recommended if you wish to use the Facebook aspect of WildFire.
Thanks for your feedback.