Random X crash when using beryl

Hello.

I'm running kubuntu Feisty on a dell laptop d810 latitude.

I got a Nvidia : 01:00.0 VGA compatible controller: nVidia Corporation Quadro NVS 110M / GeForce Go 7300 (rev a1)
Running with nvidia drivers :
ii nvidia-glx 100.14.011 NVIDIA binary XFree86 4.x driver

I've tested every kind of drivers, from nvidia-glx to nvidia-glx-new, beta drivers, nvidia.run etc...

When I launch Beryl, X got random crash, from 30 seconds, to 4 hours, it's really really random.

I can't really reproduce the situation. Sometimes it's during a mouse clic, then a virtual desktop switch, then a page down on Firefox etc...

Here is the Xorg.0.log.old :

SetClientVersion: 0 9
SetGrabKeysState - disabled
SetGrabKeysState - enabled
(II) NVIDIA(0): Setting mode "1024x768"
(II) NVIDIA(0): Setting mode "1920x1200"

Backtrace:
0: /usr/bin/X(xf86SigHandler+0x81) [0x80c5d91]
1: [0xffffe420]
2: /usr/bin/X [0x81623ad]
3: /usr/bin/X [0x815ea9f]
4: /usr/bin/X(CompositeGlyphs+0x9a) [0x814c0fa]
5: /usr/bin/X [0x8153c0c]
6: /usr/bin/X [0x814f145]
7: /usr/bin/X [0x81424ce]
8: /usr/bin/X(Dispatch+0x19f) [0x808c61f]
9: /usr/bin/X(main+0x495) [0x8074785]
10: /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xdc) [0xb7d56ebc]
11: /usr/bin/X(FontFileCompleteXLFD+0x1e1) [0x8073ab1]

Fatal server error:
Caught signal 11. Server aborting