The binary '/usr/bin/inndf' should return the free space in Kb when called with a path. But it returns ever zero ('0'). So the script 'sendbatch' doesn't work because this zero return value. BTW: the update from RedHat 5.2 to 6.0 doesn't work correctly for inn if it couldn't remove the '/usr/lib/news' directory.
*** This bug has been marked as a duplicate of 3154 ***