gnome-screensaverは無くても構わないので、pkg_deleteしてしまいました。
当然、スクリーンセーバーは使用できなくなりましたが、
ひとまず起動時にgnome-screensaverのクラッシュが報告されることはなくなりました。
(英語環境で使用するならば、これで問題なしという事ですが…)
しかし、日本語環境では相変わらず、
アプリケーションを開き、閉じると、クラッシュする状況が続いています。

startx -> gnome端末開く -> gnome端末閉じる(クラッシュ) -> ログアウト
とした時のメッセージを採取したので、下記に添付します。
お気づきの点など指摘頂けると幸いです。

xauth:  creating new authority file /home/hsmtkk/.serverauth.1177


X.Org X Server 1.4.0
Release Date: 5 September 2007
X Protocol Version 11, Revision 0
Build Operating System: FreeBSD 6.3-RC1 i386
Current Operating System: FreeBSD localhost 6.3-RC1 FreeBSD 6.3-RC1
#0: Tue Nov 27 00:32:51 UTC 2007
[メールアドレス保護]:/usr/obj/usr/src/sys/GENERIC
 i386
Build Date: 17 December 2007  09:17:31AM

        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Thu Dec 20 17:26:19 2007
(==) Using config file: "/etc/X11/xorg.conf"
(II) Module "ddc" already built-in
(II) Module "i2c" already built-in
NTSC PAL NTSC-J
finished output detect: 0
finished output detect: 1
finished output detect: 2
finished output detect: 3
finished all detect
before xf86InitialConfiguration
in RADEONProbeOutputModes
after xf86InitialConfiguration
(II) Module "ramdac" already built-in
Entering TV Save
Save TV timing tables
saveTimingTables: reading timing tables
TV Save done
init memmap
init common
init crtc1
init pll1
restore memmap
restore common
restore crtc1
restore pll1
restore LVDS
enable montype: 2
disable montype: 2
enable montype: 2
SESSION_MANAGER=local/localhost:/tmp/.ICE-unix/1201
ウィンドウ・マネージャの警告: 保存されたセッションファイルの解析に失敗しました: 行 1 の 1 文字目でエラー:
ドキュメントが空か、空白だけが含まれています
Initializing gnome-mount extension

** (nautilus:1222): WARNING **: Cannot connect to system bus:
org.freedesktop.DBus.Error.FileNotFound : Failed to connect to socket
/var/run/dbus/system_bus_socket: No such file or directory

** (nautilus:1222): WARNING **: Could not initialize hal context

Shutting down gnome-mount extension

(nautilus:1222): Liboobs-WARNING **: Failed to connect to socket
/var/run/dbus/system_bus_socket: No such file or directory
seahorse nautilus module initialized

** (gnome-panel:1215): WARNING **: Failed to establish a connection
with GDM: No such file or directory
Launching a SCIM daemon with Socket FrontEnd...
Loading simple Config module ...
Creating backend ...
Loading socket FrontEnd module ...
Starting SCIM as daemon ...
GTK Panel of SCIM 1.4.7

Launching a SCIM daemon with Socket FrontEnd...
Loading simple Config module ...
Creating backend ...
Loading socket FrontEnd module ...
Starting SCIM as daemon ...
GTK Panel of SCIM 1.4.7

This libgtop was compiled on FreeBSD 6.3-PRERELEASE i386
If you see strange problems caused by it,
you should recompile libgtop and dependent applications

warning: Unable to get location for thread creation breakpoint: generic error
Backtrace limit of 200 exceeded
/usr/local/share/bug-buddy/gdb-cmd:3: Error in sourced command file:
Backtrace limit of 200 exceeded
Backtrace limit of 200 exceeded
LibGTop-Server: pid 1272 received eof.
** Message: Could not connect to power manager: Could not get owner of
name 'org.freedesktop.PowerManagement': no such name

** (gnome-panel:1215): WARNING **: Failed to establish a connection
with GDM: No such file or directory
ウィンドウ・マネージャの警告: CurrentTime used to choose focus window; focus window
may not be correct.
ウィンドウ・マネージャの警告: Got a request to focus the no_focus_window with a
timestamp of 0.  This shouldn't happen!
seahorse nautilus module shutdown


waiting for X server to shut down disable montype: 2
finished PLL2
Entering Restore TV
Restore TV PLL
Restore TVHV
Restore TV Restarts
Restore Timing Tables
Restore TV standard
Leaving Restore TV
FreeFontPath: FPE "/usr/local/lib/X11/fonts/misc/" refcount is 3,
should be 2; fixing.

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