question about cpl6 : core_lite

[jlu@coaps_fsu_edu]

I've been running CCSM3 with latm6. A case successfully run before, with exactly same setting, cannot run again. In the directory "cpl" under the runcase directory, there appeared coredir.1 ,..., coredir.7 in which a file named " core_lite" :

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+++PARALLEL TOOLS CONSORTIUM LIGHTWEIGHT COREFILE FORMAT version 1.0
+++LCB 1.0 Sun Dec 11 17:00:51 2011 Generated by IBM AIX 5.3
#
+++ID Node 1 Process 668366 Thread 1
***FAULT "SIGSEGV - Segmentation violation"
+++STACK
# At location 0x000000010004aeac but procedure information unavailable.
# At location 0x0000000100109584 but procedure information unavailable.
__cpl_map_mod_NMOD_cpl_map_init : 0x00002138
__data_mod_NMOD_data_mapinit : 0x00000458
cpl : 0x00001cf8
---STACK
---ID Node 1 Process 668366 Thread 1
#
+++ID Node 1 Process 668366 Thread 2
+++STACK
# At location 0x0000000000000000 but procedure information unavailable.
---STACK
---ID Node 1 Process 668366 Thread 2
#
+++ID Node 1 Process 668366 Thread 3
+++STACK
# At location 0x0000000000000000 but procedure information unavailable.
---STACK
---ID Node 1 Process 668366 Thread 3
#
+++ID Node 1 Process 668366 Thread 4
+++STACK
# At location 0x0000000000000000 but procedure information unavailable.
---STACK
---ID Node 1 Process 668366 Thread 4
#
+++ID Node 1 Process 668366 Thread 5
+++STACK
# At location 0x0000000000000000 but procedure information unavailable.
---STACK
---ID Node 1 Process 668366 Thread 5
#
+++ID Node 1 Process 668366 Thread 6
+++STACK
# At location 0x0000000000000000 but procedure information unavailable.
---STACK
---ID Node 1 Process 668366 Thread 6

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This error never appeared in the runs with the same setting. Would anyone tell me what it is about? Thanks.