Why would PostgreSQL close the 'backend unexpectedly'

Hi Folks,

I'm running a server, 1gig ram, 1ghz cpu, enough hd space. On it, s'pose you
guessed it, i'm having some problems with PostgresSQL. Also on the server,
there is a website, about 70 active users online at the same time. Results
in quite some memory usage. The gig is used in full for the most of the
time.

Now comes the problem, every now and then, it seemed to be totally random
(since it is a computer, it can't be, I know), there appears an error in the
error log saying: PgRead() connection failed: the database system closed
backend unexpectedly. It might be in some other phrase (somehow, the back of
my mind is whispering: Backend closed the channel unexpectedly), but just at
this moment I couldn't find the exact words in the logs. If you know how to
solve this problem, you'll probalby know what I mean.

The problem seems to be something with memory, the the small development
server we also run it gives the same error when it's out of mem. Is there
maybe a way to bypass this and perhaps let postgres wait for some time when
he thinks to be out of memory. It's quite unwanted for the system to
generete such errors .. don't have to explain that I guess.

Thanks for anyone who comes out with an idea. I'll buy you a beer if I once
meet you.

Wouter