When a user deleted their entire library (and they do it often for some reason), the quota is still all out of wack and shows in the red -- only solution is to sync the library by running page=importmedia
This was in a bug report a while back and I think you indicated the problem was corrected but that is not the case -- running the very latest Centova Cast v3.0.0rc2 as of 2/22/2013 on 2 different servers with same problem