Failed to select source

Squid 2.0.PATCH2, Solaris 2.5.1

Anyone know what "failed to select source" means ? Doesn't sound good... :-)
We're inside a firewall - could this message be caused if all parents were
"down" ? What will squid do in this case ? Does it wait ? or say not accessible
or something ? how does the client see the problem ? (I'm sure I'll find out
fairly quickly from our users if it happens again :-)

---
1998/10/12 10:23:25| clientReadRequest: FD 73 Invalid Request
1998/10/12 10:24:32| Failed to select source for
'http://www.irish-times.com/whitedot.gif'
1998/10/12 10:24:32|   always_direct = -1
1998/10/12 10:24:32|    never_direct = 1
1998/10/12 10:24:32|        timedout = 1
[10:25am] root@squid:~squid/logs 118# tail -1000 access.log|grep whitedot.gif
908184272.047     44 164.48.142.93 TCP_MISS/503 1274 GET
http://www.irish-times.ie/whitedot.gif - TIMEOUT_NO_DIRECT_FAIL/- -
908184292.501   3843 164.48.142.93 TCP_MISS/200 365 GET
http://www.irish-times.ie/whitedot.gif -
TIMEOUT_FIRST_UP_PARENT/cacher-int.wise.edt.ericsson.se image/gif
Cheers,
Niall
-- 
Niall Doherty          | mailto:ndoherty@eei.ericsson.se
Systems Engineer       | http://www.ericsson.ie
Voice: +353 1 207 7506 | Ericsson Systems Expertise Ltd.,
Fax:   +353 1 207 7115 | Beech Hill, Clonskeagh, Dublin 4, Ireland.