I have started getting these in my log.  What does this mean and what do I need to do?

 Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset): assertion failed: (offset < 0x40000000)

Dec 12 23:29:44 mail dovecot: imap(jeff@stariontech.com): Error: Raw backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0x3cafa) [0x7f38c5a2cafa] -> /usr/lib64/dovecot/libdovecot.so.0(+0x3cb46) [0x7f38c5a2cb46] -> /usr/lib64/dovecot/libdovecot.so.0(+0x16e2a) [0x7f38c5a06e2a] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_uint32_to_offset+0x74) [0x7f38c5d0d3f4] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x81abd) [0x7f38c5cf3abd] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_cache_compress+0x77) [0x7f38c5cf4247] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_sync_commit+0x1d2) [0x7f38c5d08012] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x5fd88) [0x7f38c5cd1d88] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x570a0) [0x7f38c5cc90a0] -> /usr/lib64/dovecot/libdovecot-storage.so.0(maildir_storage_sync_force+0x52) [0x7f38c5cc94c2] -> /usr/lib64/dovecot/libdovecot-storage.so.0(maildir_file_do+0x99) [0x7f38c5cc9f49] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x59b7f) [0x7f38c5ccbb7f] -> /usr/lib64/dovecot/libdovecot-storage.so.0(index_mail_set_seq+0x112) [0x7f38c5cb64f2] -> /usr/lib64/dovecot/libdovecot-storage.so.0(index_storage_search_next_nonblock+0x16b) [0x7f38c5cbae9b] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mailbox_search_next_nonblock+0x20) [0x7f38c5ca2240] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mailbox_search_next+0x26) [0x7f38c5ca2296] -> dovecot/imap(imap_fetch_more+0x2bf) [0x41221f] -> dovecot/imap(cmd_fetch+0x42c) [0x40a33c] -> dovecot/imap() [0x40f90d] -> dovecot/imap() [0x40f9fa] -> dovecot/imap(client_handle_input+0x135) [0x40fc25] -> dovecot/imap(client_input+0x5f) [0x41054f] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_call_io+0x48) [0x7f38c5a37e98] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_handler_run+0x9f) [0x7f38c5a38e0f] -> /usr/lib64/dovecot/libdovecot.so.0(io_loop_run+0x28) [0x7f38c5a37e28] -> /usr/lib64/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f38c5a26293] -> dovecot/imap(main+0x2f9) [0x418849] -> /lib64/libc.so.6(__libc_start_main+0x10

Dec 12 23:29:44 mail dovecot: master: Error: service(imap): child 11157 killed with signal 6 (core dumps disabled)