How to make a bootable disk from an image with Toast?
Toast:


"Do not mount the Disk Image first!"
Launch "Toast.app"
Click "Data" icon (upper left) and choose ISO 9660
Select "Copy" icon (upper left) and choose Image File
Click "Select" and "Choose a Disk Image File" from the dialog (do not drag and drop).
Click "Burn" et voilà.






Disk Utility: 


Launch "Disk Utility.app"
Click "Burn" icon (upper left)
"Select image to burn" from the dialog (do not drag and drop).
Insert CD / DVD
Click "Burn" using the dialog.






Most effective Option:


Launch "Terminal.app"
Use the following command(s). Replace "imagefile.dmg/.iso" with your dir and/or prefferd name.

hdiutil convert imagefile.dmg -format UDTO -o imagefile.iso                
hdiutil burn Imagename.iso



This method uses the exact pre-installed function of "Disk Utility.app" only without the GUI!