Typically this Error message “:ERROR: Not enough memory”, from many customers contacting me on support, asking this question about this error, I find out that even though on our product requirments that we require 512MB, sometimes the motherboards built in video will take from this. Can you tell me if the motherboard is subtracting from this (16, 32 or 64)???
Also try after POST, enter the Escape key to see if you can get into a basic menu and select Rescue mode.

But if possible can you add some additional memory just to test or test with another system board (also disable any power management features) ??