Unable to extend LV

Hi all.

I have a Logical volume that I can't extend, with this error message:

server171:root:/root# lvextend -L +1024M -v /dev/aplic_vg/siteminderwa_lv
    Finding volume group aplic_vg
    Archiving volume group "aplic_vg" metadata (seqno 75).
  Extending logical volume siteminderwa_lv to 1.98 GB
    Found volume group "aplic_vg"
    Found volume group "aplic_vg"
    Loading aplic_vg-siteminderwa_lv table (253:40)
  device-mapper: reload ioctl failed: Invalid argument
  Failed to suspend siteminderwa_lv
    Creating volume group backup "/etc/lvm/backup/aplic_vg" (seqno 76).

Any idea about which could be the root cause?

server171:root:/root# vgdisplay aplic_vg
  --- Volume group ---
  VG Name               aplic_vg
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  75
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                24
  Open LV               21
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               81.00 GB
  PE Size               4.00 MB
  Total PE              20735
  Alloc PE / Size       20474 / 79.98 GB
  Free  PE / Size       261 / 1.02 GB
  VG UUID               d52Ecp-fgib-Z1vs-AcCh-ZY26-2uJF-lhHQbk

server171:root:/root# lvdisplay /dev/aplic_vg/siteminderwa_lv
  --- Logical volume ---
  LV Name                /dev/aplic_vg/siteminderwa_lv
  VG Name                aplic_vg
  LV UUID                f9XCaT-6FR2-0cc3-O3QY-qIn2-1XZO-GQb6Zu
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                1000.00 MB
  Current LE             250
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:40

server171:root:/root# lvscan | grep siteminder
  ACTIVE            '/dev/aplic_vg/siteminderwa_lv' [1000.00 MB] inherit

server171:root:/root# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.8 (Tikanga)