Streaming Replication in PostgreSQL9.0 b4: Standby dropping connections

Hi,

In PG9.0-b4 I have successfully set up a primary-secondary pair with
streaming replication, with the secondary in hot_standby mode.

I have an application on the standby (and primary) which has constant
connections open to the database. Occasionally it refreshes its cache of
data from the hot_standby secondary server.
I am intermittently getting and error when updating the application's cache.
When I check the PostgreSQL logs with the same timestamp, I see the
following messages:

FATAL: terminating connection due to conflict with recovery
DETAIL: User query michg have needed to see row versions that must be
removed.
HINT: In a moment you should be able to reconnect to the database and repeat
your command.

Now, this message seems to explain the problem, but I couldn't find anything
in the streaming replication documentation indicating that this sort of
thing might occur. Is there any way to avoid it?
Any further information about this specific problem?

Thanks in advance,

Chip