I have the exact same problem on my MB. Since I had been wanting to do a reinstall of OS X, and clear out some old 'garbage' (I still had PPC apps and stuff floating around from my PBG4 migration), seeing the permission issue made me do it. I am glad I did it because I freed up a lot of space removing languages and not installing certain Apps that I don't use. Long story short, I still have the permissions issue. oh well, I guess I just won't click repair permissions anymore if it is aberrant at the moment.