do you uses compiz/beryl activated on boot ? (and shutdown ?)
Did you tryed to disable aiglx with this in xorg.conf
Option "AIGLX" "off"
Actually i have the problem solved with this and enabling composite with my quadro fx500 (not sure it is enabled by default with fedora 6/7)
Option "Composite" "Enable"
(i know this prevent to have the above issue with previous nvidia driver version and beryl, not sure i can work with compiz but you may be interested in
Also i wonder if it is mandatory to have acpid installed and started on boot to get the driver work... or using (to disable if acpid is not running):
Option "ConnectToAcpid" "0"
If this is mandatory, we (at rpm.livna.org - mean firewingl and I) will consider to add acpid as a requirement... and set aiglx off by default for all livna users with nvidia (100.xx.xx, 96xx, legacy ?!)