Problem with "$@" variable

[w8sdz]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: freebsd5.4
Compiler: cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='freebsd5.4' -DCONF_MACHTYPE='i386-portbld-freebsd5.4' 
-DCONF_VENDOR='portbld' -DLOCALEDIR='/usr/local/share/locale' -DPACKAGE='bash' 
-DSHELL  -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib  -I/usr/local/include 
-O -pipe
uname output: FreeBSD mail.petersen.net 5.4-RELEASE FreeBSD 5.4-RELEASE #0: Sun 
May  8 10:21:06 UTC 2005     
root@harlow.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
Machine Type: i386-portbld-freebsd5.4

Bash Version: 4.0
Patch Level: 10
Release Status: release

Description:
        I use the following function in my .profile to make the
hostname and current path appear in my X-Windows rxvt terminal
titlebar:

cd()
{
   builtin cd "$0" && xtitle $HOST: $PWD
}

This no longer works correctly since I upgraded bash to the version
listed above.  Instead, when I use cd without an argument the following
error message:

-bash: $@: unbound variable

Repeat-By:
        Add the above function to your .profile.  When you cd
with an argument as in cd /var/tmp it works as expected.  When
you wish to return to your home directory do a cd with no argument.
The error appears every time.

Keith Petersen
w8sdz@mail.petersen.net