I've upgraded the Bios (the current version is A03 since the 2007/04/10) and tried to installed the 100.14.03 driver.Of course, I've uninstalled the older 9755 driver before.
The problem persits with the latest 100.14.03 driver giving the report attached.
The new point is that it does not produce the same error. The log seems to say
(--) NVIDIA(GPU-1): Connected display device(s) on Quadro NVS 440 at PCI:9:0:0:
0: /usr/bin/Xorg(xf86SigHandler+0x81) [0x80e4ea1]
2: /usr/lib/xorg/modules/drivers/nvidia_drv.so(_nv001046X+0x1a) [0xb73c2606]
Fatal server error:
Caught signal 11. Server aborting
Do you know what it means ?