Well ... could be but I'm guessing he's just managed to write a query that's broken PG. The message from the postmaster is given whenever a backend dies, which in my experience has always been due to a query that PG simply barfs on.
Note that he's not getting the invalid block error - I think that was due to inadequate stack space.
Of course, it's a good idea to run RAM and other system tests, just on general principle.
But I think he's going to find there's a PG-breaking query at the root of this new symptom he's seeing.
