The following script prints "PACKED" and dumps core.

<?php

        $dbname = "/tmp/testdb.dbf";
        $rarr = array("Polasek","Vonasek");
        $zme = array("Vonasek","Polasek");

        $def = array(
                array("name",   "C",    50),
		array("name2",   "C",    50),
        );

        if (!dbase_create($dbname, $def))
                print "FAILED\n";

        $dbid = dbase_open($dbname,2);

        if (!dbase_add_record($dbid,$rarr))
                print "ADD RECORD FAILED!";

        if (dbase_pack($dbid)) {
                echo "PACKED\n";
        }

        if (dbase_replace_record($dbid,$zme,1)) {
                echo "RECORD CHANGED\n";
        }else{
                echo "CHANGE FAILED\n";
        }
?}

==================================================
'./configure' '--with-config-file-path=/etc'
'--with-apxs=/usr/sbin/apxs' '--enable-versioning'
'--enable-inline-optimization' '--enable-shared'
'--enable-track-vars' '--enable-magic-quotes'
'--enable-safe-mode' '--with-db2' '--with-db3' '--with-gdbm'
'--with-gd=shared' '--enable-debugger' '--enable-sysvsem'
'--enable-sysvshm' '--enable-dbase' '--with-readline'
'--without-mysql'
==================================================
gdb backtrace:

Core was generated by `php dbftest.php'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libpam.so.0...(no debugging
symbols found)...done.
Loaded symbols for /lib/libpam.so.0
Reading symbols from /lib/libdl.so.2...done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /usr/lib/libz.so.1...done.
Loaded symbols for /usr/lib/libz.so.1
Reading symbols from /usr/lib/libjpeg.so.62...done.
Loaded symbols for /usr/lib/libjpeg.so.62
Reading symbols from /usr/lib/libpng.so.2...done.
Loaded symbols for /usr/lib/libpng.so.2
Reading symbols from /lib/libdb-3.1.so...done.
Loaded symbols for /lib/libdb-3.1.so
Reading symbols from /usr/lib/libdb.so.3...done.
Loaded symbols for /usr/lib/libdb.so.3
Reading symbols from /usr/lib/libgdbm.so.2...done.
Loaded symbols for /usr/lib/libgdbm.so.2
Reading symbols from /lib/libresolv.so.2...done.
Loaded symbols for /lib/libresolv.so.2
Reading symbols from /lib/libm.so.6...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libcrypt.so.1...done.
Loaded symbols for /lib/libcrypt.so.1
Reading symbols from /lib/libnsl.so.1...done.
Loaded symbols for /lib/libnsl.so.1
Reading symbols from /usr/lib/libttf.so.2...done.
Loaded symbols for /usr/lib/libttf.so.2
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
#0  0x80caea1 in _zval_ptr_dtor ()
(gdb) bt
#0  0x80caea1 in _zval_ptr_dtor ()
#1  0x80d6c15 in zend_hash_destroy ()
#2  0x80d1da3 in _zval_dtor ()
#3  0x80caeb6 in _zval_ptr_dtor ()
#4  0x8103f4a in execute ()
#5  0x80d31df in zend_execute_scripts ()
#6  0x805ec91 in php_execute_script ()
#7  0x805cf29 in main ()
#8  0x401f3a7c in __libc_start_main (main=0x805c748 <main>,
argc=2, ubp_av=0xbffffab4,
    init=0x805b204 <_init>, fini=0x810e2fc <_fini>,
rtld_fini=0x4000d684 <_dl_fini>,
    stack_end=0xbffffaac) at ../sysdeps/generic/libc-start.c:111