I have enabled these two things:

• Placing the mouse-pointer in the bottom-left corner of any display makes the screensaver appear
• After the screensaver or stand-by has ended, ask for password

However, this combination always leads to this (Black Screen of Death) after entering the screensaver with the bottom-left corner:

Here are my system specs:

Hardware Overview:

  Model Name:   iMac
  Model Identifier: iMac9,1
  Processor Name:   Intel Core 2 Duo
  Processor Speed:  2,66 GHz
  Number Of Processors: 1
  Total Number Of Cores:    2
  L2 Cache: 6 MB
  Memory:   2 GB
  Bus Speed:    1,07 GHz
  Boot ROM Version: IM91.008D.B08
  SMC Version (system): 1.44f0
  Serial Number (system):   W89171JF0TF
  Hardware UUID:    323A90F0-8A2F-5057-B501-2087489E0DFF

System Software Overview:

  System Version:   Mac OS X 10.6.3 (10D573)
  Kernel Version:   Darwin 10.3.0
  Boot Volume:  Macintosh HD
  Boot Mode:    Normal
  Computer Name:    YOU SHOULD NOT KNOW THIS
  User Name:    YOU SHOULD NOT KNOW THIS
  Secure Virtual Memory:    Not Enabled
  64-bit Kernel and Extensions: No
  Time since boot:  11:46

Can anyone help me? Thanks