The error occurs only on Android and it looks that the facebook sdk wasn't included in the final apk file. Since v4.3.3, the facebook unity sdk for android has been distributed as a project instead of the jar file. I tried the jar file version working fine, but the project version doesn't work.
As far as I know, the facebook sdk project has to be in android-libraries directory in StaggingArea when building for android. So I checked if it exists, there was an directory named "facebook" in android-libraries of StaggingArea but it was empty inside the directory "facebook". I'm not sure whether this problem is related to the Unity or not. The android version required by the facebook sdk was installed. Curiously enough, there are android sdk files for android in StaggingArea/android-libraries on other seats.
Is there anybody who experienced in this kind of issue?
