ext4 filesystems larger than 16T

[Brad White]

I have a LVM based ext4 filesystem on RHEL 5.4.  The LV is just over 21T, but I am unable to extend the filesystem past the 15T that it is currently using.
I get this error from resize4fs:

resize4fs 1.41.5 (23-Apr-2009)
resize4fs: File too large while trying to determine filesystem size

lvdisplay:

 --- Logical volume ---
  LV Name                /dev/ProgramArchive/ProgramArchive01
  VG Name                ProgramArchive
  LV UUID                g7Ndek-tZzc-irZX-7yiB-pbAC-NCHZ-7QetqV
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                21.82 TB
  Current LE             5720062
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:6


I guess large filesystem support still is not present in ext4?  I this the case, or do newer versions of the ext2/3/4 tools permit growing a filesystem past 16T?