HELP!! IP Cache is overflowing!

re,

Squid 1.1.6, FreeBSD 2.x.

Anybody can explain following message in cache.log?

97/02/13 09:56:10| HELP!! IP Cache is overflowing!

Sometimes am seeing this message too often, practicaly in a few seconds.
I would not say it's a problem :), but squid begin to report to users the
next message:

The following error was encountered:

     DNS name lookup failure

This means that:

    The named host probably does not exist.

...and I suppose it related with the first message in cache.log.

Any suggestions?

-- 
Igor Vinokurov, JSB "Inkombank"