William Bahn wrote
The Console window reports NullPointer Exceptions. Sometimes the simulation locks up immediately after the first of these appear, but other times it continues running and many more of these appear before it finally locks up.
I've seen this happen when the Hardware Simulator runs out of memory.
It is very important to build the memory parts in the 'a' and 'b' subdirectories under projects/03, as structured in the distribution .zip file. Do not copy any of your other HDL sources into these subdirectories, especially don't copy any of the RAM*.hdl files from 'a' into 'b'.