Re: Brightness control not working with nVidia driver
there are two scripts available in Ubuntu, hybernate.sh and hybernatebtm.sh, same for sleep. Try which one of the two works for you by launching them from the command line and then put the good one in the acpi event. Don't ask me what is the difference between the two because I have no idea. For me for hybernate it works the -btm version and for suspend the plain one, or the other way around, I haven't got my laptop in front of me now.
For kernel -17 acpi_listen worked by reinstalling the kernel via synaptic, go figure.