[OS X] iMac DV SE fails to sleep.

A regular Guy wrote on :

Ok. iMac DV SE 500 Mhz 640 MB RAM running 10.1.x (problem exists in all builds)

This machine will NOT go to sleep and the screen saver will NOT activate. It can be put to sleep and the screen saver can be manually activated.

So what's the problem? Here's what I find when I look at the system.log:

Feb 25 08:48:55 localhost mach_kernel: System Sleep Feb 25 08:48:59 localhost mach_kernel: System Wake Feb 25 08:48:59 localhost mach_kernel: Wake event 0020

What is 'Wake event 0020?' It APPEARS to be what is preventing auto-sleep. Anyone have an insight on this?

BTW, where can I find information about interrepting all the other information in the system.log? For example, it indicates:

Feb 25 07:19:59 localhost mach_kernel: verify_kmod(): kmod "com.Wacom.iokit.TabletDriver" has an invalid version. Feb 25 07:19:59 localhost mach_kernel: load_kernel_extension(): load_kmod() failed for kmod "com.Wacom.iokit.TabletDriver". Feb 25 07:19:59 localhost mach_kernel: IOCatalogue: com.Wacom.iokit.TabletDriver cannot be loaded.

BUT, the Wacom Tablet works fine! So what does this mean?

DOCUMENTATION, DOCUMENTATION, DOCUMENTATION! Apple, where is it?