"Show Log"

[teasip]

I have a schedule setup to auto copy my Intel iMac on Sat. mornings five minutes after I set the Mac to "wake up". Whenever I click "Show Log" nothing happens. I have just manual backed up my drive (onto a WD FW/USB ext. HD) and again nothing happens when I click "Show Log". I have this happen more often than not (which implies the log being accessable from time to time). Why?