Freeze with dual screen

[Vincent BOURGEOIS]

Binary package hint: plymouth

My computer have a graphical card with 2 video outputs (GeForce 9500 GT).
I connected 2 monitors : one in the DVI output with a resolution of 1680 x 1050 and one in the VGA output with a resolution of 1024 x 768.

I test the last version of ubuntu (10.04 beta2).
During the boot of my computer, the system freeze while viewing the splash screen.

I tried to unplugged my VGA screen before the boot. The system has not freeze.
I also tried to boot my computer with both monitors connected and I removed the parameter "splash" in grub. The system has not freeze during the boot.
This problem also appeared in booting on liveCD.

How is it possible to boot my system by activating the splash screen with my 2 screens connected ?

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: plymouth 0.8.1-4ubuntu1
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic i686
Architecture: i386
Date: Wed Apr 21 20:56:08 2010
DefaultPlymouth: /lib/plymouth/themes/ubuntu-logo/ubuntu-logo.plymouth
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Beta i386 (20100406.1)
MachineType: Dell Inc. Inspiron 530
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-19-generic root=UUID=1ed39d56-be93-4711-bc4b-0f6f2f0080c8 ro quiet
ProcEnviron:
 LANG=fr_FR.utf8
 SHELL=/bin/bash
ProcFB: 0 nouveaufb
SourcePackage: plymouth
TextPlymouth: /lib/plymouth/themes/ubuntu-text/ubuntu-text.plymouth
dmi.bios.date: 02/24/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.0.18
dmi.board.name: 0RY007
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: OEM
dmi.modalias: dmi:bvnDellInc.:bvr1.0.18:bd02/24/2009:svnDellInc.:pnInspiron530:pvr:rvnDellInc.:rn0RY007:rvr:cvnDellInc.:ct3:cvrOEM:
dmi.product.name: Inspiron 530
dmi.sys.vendor: Dell Inc.