The following files :

17:01 [webase3:p3] titi:~/html% cat test.php
<?
  include("testinc.php");
?>
17:01 [webase3:p3] titi:~/html% cat testinc.php 
<?
if (TRUE) {
class toto { }
}
?>

produce when you execute the first one :

Program received signal SIGSEGV, Segmentation fault.
zval_dtor (zvalue=0xc1e78da8) at zend_variables.c:56
56              if (zvalue->type==IS_LONG) {
(gdb) bt
#0  zval_dtor (zvalue=0xc1e78da8) at zend_variables.c:56
#1  0x80750ea in execute (op_array=0x80ee508) at zend_execute.c:1893
#2  0x8056dcc in php_execute_script (primary_file=0xbffff948) at main.c:1133
#3  0x805c6a1 in main (argc=2, argv=0xbffff9b8) at cgi_main.c:448