Looks like it doesn't like some M4A files you are trying to auto import. A few files like this one (same directory):
/Volumes/Musik A-S/Shostakovich, Dmitri (1906 - 1975)/Sinfonien/Sinfonie Nr. 10 e-moll, op. 93/Shostakovich_Sinfonie10_Rattle_BPO_Proms08/01a. Ansage.m4a
Looks like they changed some stuff with m4a in build 68. I would go back to a version before 68 and see if it works ok. If so, it's probably the changes. If not, it's probably broken files.
Brian.