WTF is going on with PG_VERSION?

Greetings.

The problem is: from time to time, PostgreSQL seems to crash.
Inspection of the logs revealed the following:

Сен 18 15:53:06 arbat logger: FATAL 1:  File '/var/lib/pgsql/PG_VERSION' does not exist or no read permission.

Well, '/var/lib/pgsql/PG_VERSION' does exist, it has read permission
for user 'postgres' (I made it world readable, in fact, after I
discovered this).

Now, two questions:
1) Who the hell needs to read this file?
2) Why can't he do it?


--
Yours, Alexey V. Borzov