As requested in the FAQ, here is by backtrace of this error. this looks very similar to some other bug reports. Just thought I throw in some more debugging info.

Some background:

DEC Alpha 4/266 96MB RAM 2GHD
Running RedHat Linux 6.0 upgraded from 5.2 (completely stock)

PHP compiled as an Apache module. All works well unless I try to "require" or "include" a document. Even if 
the document referenced is empty segfault occours. If the referenced file can not be found a regular error is 
displayed and no segfault or core.

(gdb) run -X -f /etc/httpd/conf/httpd.conf
Starting program: /usr/sbin/httpd -X -f /etc/httpd/conf/httpd.conf

Program received signal SIGSEGV, Segmentation fault.
0x2000065595c in _IO_new_fclose (fp=0x120188680) at iofclose.c:45
iofclose.c:45: No such file or directory.
(gdb) bt
#0  0x2000065595c in _IO_new_fclose (fp=0x120188680) at iofclose.c:45
#1  0x2000251929c in end_current_file_execution (retval=0x11fffe168)
    at language-scanner.lex:374
#2  0x2000251add0 in lex_scan (phplval=0x11ffff6a0)
    at language-scanner.lex:1186
#3  0x200024ccb74 in read_next_token (tcm=0x20002650a20,
token=0x11fffe1f0,
    phplval=0x11ffff6a0) at token_cache.c:142
#4  0x200024c2004 in phplex (phplval=0x11ffff6a0) at main.c:483
#5  0x2000250b31c in phpparse () at /usr/local/share/bison.simple:431
#6  0x200024c40fc in php3_parse (yyin=0x120188680) at main.c:1534
#7  0x200024c446c in apache_php3_module_main (r=0x12017e4e0, fd=19,
    display_source_mode=0, preprocessed=0) at main.c:1914
#8  0x200024c0c2c in send_php3 ()
#9  0x200024c0d04 in send_parsed_php3 ()
(gdb)