Backtrace: (this is produced by the current version of IMP reading a very large mailbox. But it doesn't involve an IMAP function, so I'm not sure where to look).

Program received signal SIGSEGV, Segmentation fault.
0x8069f1f in read_next_token (tcm=0x81a36e0, token=0xbfffe6f8, 
    phplval=0xbfffeb88) at token_cache.c:177
177		return (*token)->token_type;
(gdb) bt
#0  0x8069f1f in read_next_token (tcm=0x81a36e0, token=0xbfffe6f8, 
    phplval=0xbfffeb88) at token_cache.c:177
#1  0x8063fe7 in phplex (phplval=0xbfffeb88) at main.c:496
#2  0x809ff45 in phpparse () at /usr/lib/bison.simple:431
#3  0x8065565 in php3_parse (yyin=0x81d5d78) at main.c:1548
#4  0x8065740 in apache_php3_module_main (r=0x81d3414, fd=19, 
    display_source_mode=0, preprocessed=0) at main.c:1934
#5  0x8062df9 in send_php3 ()
#6  0x8062e5a in send_parsed_php3 ()
#7  0x80b1803 in ap_invoke_handler ()
#8  0x80c4549 in process_request_internal ()
#9  0x80c45ac in ap_process_request ()
#10 0x80bc33e in child_main ()
#11 0x80bc4cc in make_child ()
#12 0x80bc629 in startup_children ()
#13 0x80bcc46 in standalone_main ()
#14 0x80bd3b3 in main ()
#15 0x400d0cb3 in __libc_start_main (main=0x80bd08c <main>, argc=2, 
    argv=0xbffffba4, init=0x804b57c <_init>, fini=0x8124cec <_fini>, 
    rtld_fini=0x4000a350 <_dl_fini>, stack_end=0xbffffb9c)
    at ../sysdeps/generic/libc-start.c:78