rm: Directory not empty ..(had tried chflag ...)

[K.C.Huang-MLC]

Dear All:
  I running fsck -y to a device, and I delete some files in the same =
time .
  I found there were some files could'nt be delete..

  message:
      rm: old_files: Directory not empty

  I had tried=20
     chflags -R noschg  old_files
     rm -rf old_files

 thanks in advance ..^^