7337 Xserver crashes and restart gdm

This is my system log

Sep 10 18:58:51 electro-ubuntu NetworkManager: <debug> [1189443531.647020] nm_hal_device_added(): New device added (hal udi is '/org/freedesktop/Hal/devices/volume_label_Datos_personales__06/jul/2007').
Sep 10 18:58:51 electro-ubuntu kernel: [28904.804000] UDF-fs: No VRS found
Sep 10 18:58:52 electro-ubuntu kernel: [28904.924000] ISO 9660 Extensions: Microsoft Joliet Level 3
Sep 10 18:58:52 electro-ubuntu kernel: [28905.120000] ISO 9660 Extensions: RRIP_1991A
Sep 10 18:59:37 electro-ubuntu gdm[5136]: WARNING: gdm_slave_xioerror_handler: ha ocurrido un error fatal de X - Reiniciando :0
Sep 10 18:59:39 electro-ubuntu kernel: [28951.736000] agpgart: Found an AGP 3.5 compliant device at 0000:00:00.0.
Sep 10 18:59:39 electro-ubuntu kernel: [28951.736000] agpgart: Device is in legacy mode, falling back to 2.x
Sep 10 18:59:39 electro-ubuntu kernel: [28951.736000] agpgart: Putting AGP V2 device at 0000:00:00.0 into 4x mode
Sep 10 18:59:39 electro-ubuntu kernel: [28951.736000] agpgart: Putting AGP V2 device at 0000:01:00.0 into 4x mode
Sep 10 18:59:56 electro-ubuntu hcid[5091]: Default passkey agent (:1.31, /org/bluez/passkey) registered
Sep 10 18:59:56 electro-ubuntu hcid[5091]: Default authorization agent (:1.31, /org/bluez/auth) registered
Sep 10 19:00:00 electro-ubuntu NetworkManager: <info> Updating allowed wireless network lists.
Sep 10 19:00:00 electro-ubuntu NetworkManager: <WARN> nm_dbus_get_networks_cb(): error received: org.freedesktop.NetworkManagerInfo.NoNetworks - There are no wireless networks stored..
Sep 10 19:03:28 electro-ubuntu gdm[7337]: WARNING: gdm_slave_xioerror_handler: ha ocurrido un error fatal de X - Reiniciando :0
Sep 10 19:03:54 electro-ubuntu dhclient: DHCPREQUEST on eth0 to 10.127.37.28 port 67
Sep 10 19:03:54 electro-ubuntu hcid[5091]: Default passkey agent (:1.43, /org/bluez/passkey) registered
Sep 10 19:03:54 electro-ubuntu hcid[5091]: Default authorization agent (:1.43, /org/bluez/auth) registered
Sep 10 19:03:54 electro-ubuntu dhclient: DHCPACK from 10.127.37.28
Sep 10 19:03:54 electro-ubuntu dhclient: bound to 85.137.60.204 -- renewal in 3024 seconds.
Sep 10 19:03:57 electro-ubuntu NetworkManager: <info> Updating allowed wireless network lists.
Sep 10 19:03:57 electro-ubuntu NetworkManager: <WARN> nm_dbus_get_networks_cb(): error received: org.freedesktop.NetworkManagerInfo.NoNetworks - There are no wireless networks stored..

I am playing with mplayer a movie and when press stop buttom the system reboot.
I use compiz-fusion and i dont see any configuration about compiz when its crashes and run my metacity ( only i use Compiz Setting Manager )
Sorry i am spanish my english is very bad.
If you send me a message about more information, please tell me how to do, because i dont know much more than ubuntu or Linux.