The crypt function is causing a floting point exception when used without a salt. I have been able to reproduce this crash using this simple code:
   <? echo crypt('blah'); ?>

My PHP is configuring is this:
 '--disable-debug' \
 '--enable-track-vars' \
 '--with-apxs=/usr/local/apache/bin/apxs' \
 '--with-mysql' \
 '--with-gdbm=/usr/local' \
 '--enable-versioning' \
 '--with-pdflib' \
 '--with-cybercash=/root/src/mck/mck-3.2.0.6-
i386-pc-freebsdelf3.2'

Here is the backtrace I pulled from gdb:
0x282b4905 in php_if_crypt (ht=1, return_value=0x8294c0c, this_ptr=0x0,
    return_value_used=1) at crypt.c:153
153                     srand48((unsigned int) time(0) * getpid() * (php_combined_lcg() * 10000.0));

As far as I can tell, the exception doesn't happen when I enter a salt.  I'm using the MD5 password scheme on my FreeBSD box, instead of DES.