I am hitting this issue on Debian 7.0 Wheezy with NetgearNAS

It comes randomly when i try to access any directory in Share 

below is stack trace 

can someone please make me understand what can be cause 

  PANIC (pid 29219): internal error
[2013/04/05 09:33:12.770526,  0] ../source3/lib/util.c:921(log_stack_trace)
  BACKTRACE: 29 stack frames:
   #0 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(log_stack_trace+0x1a) [0x7f14c7fa98fa]
   #1 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(smb_panic_s3+0x20) [0x7f14c7fa99d0]
   #2 /usr/lib/x86_64-linux-gnu/libsamba-util.so.0(smb_panic+0x2f) [0x7f14c94d678f]
   #3 /usr/lib/x86_64-linux-gnu/libsamba-util.so.0(+0x1d986) [0x7f14c94d6986]
   #4 /lib/x86_64-linux-gnu/libpthread.so.0(+0xf030) [0x7f14c96fd030]
   #5 /lib/x86_64-linux-gnu/libc.so.6(+0x80e21) [0x7f14c6683e21]
   #6 /usr/lib/x86_64-linux-gnu/samba/libCHARSET3.so(push_ascii+0x36) [0x7f14c2c40256]
   #7 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(+0xecc96) [0x7f14c90a5c96]
   #8 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(+0xee9d6) [0x7f14c90a79d6]
   #9 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(smbd_dirptr_lanman2_entry+0xc8b) [0x7f14c90aa9eb]
   #10 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(smbd_smb2_request_process_find+0x965) [0x7f14c91028a5]
   #11 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(smbd_smb2_request_dispatch+0x99d) [0x7f14c90f397d]
   #12 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(+0x13b12f) [0x7f14c90f412f]
   #13 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(+0x137e6c) [0x7f14c90f0e6c]
   #14 /usr/lib/x86_64-linux-gnu/samba/libsamba-sockets.so(+0xb2a2) [0x7f14c7d762a2]
   #15 /usr/lib/x86_64-linux-gnu/samba/libsamba-sockets.so(+0xad74) [0x7f14c7d75d74]
   #16 /usr/lib/x86_64-linux-gnu/samba/libsamba-sockets.so(+0x9bc4) [0x7f14c7d74bc4]
   #17 /usr/lib/x86_64-linux-gnu/libtevent.so.0(tevent_common_loop_immediate+0xe2) [0x7f14c6991b92]
   #18 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(run_events_poll+0x47) [0x7f14c7fc08c7]
   #19 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(+0x3dce6) [0x7f14c7fc0ce6]
   #20 /usr/lib/x86_64-linux-gnu/libtevent.so.0(_tevent_loop_once+0x90) [0x7f14c6991310]
   #21 /usr/lib/x86_64-linux-gnu/samba/libsmbd_base.so(smbd_process+0xa63) [0x7f14c90e2573]
   #22 /usr/sbin/smbd() [0x40a374]
   #23 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(run_events_poll+0x353) [0x7f14c7fc0bd3]
   #24 /usr/lib/x86_64-linux-gnu/libsmbconf.so.0(+0x3dd6b) [0x7f14c7fc0d6b]
   #25 /usr/lib/x86_64-linux-gnu/libtevent.so.0(_tevent_loop_once+0x90) [0x7f14c6991310]
   #26 /usr/sbin/smbd(main+0x136c) [0x406f3c]
   #27 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7f14c6621ead]
   #28 /usr/sbin/smbd() [0x4072d1]