I have found hundreds of these errors in my /var/log/firebird.log under
Debian Sid running Classic Firebird 1.0.2-2 on a Dual Xeon CPU:

- INET/inet_error: send errno = 32
- INET/inet_error: read errno = 104
- Database: /var/lib/firebird/system/isc4.gdb
internal gds software consistency check (cannot start thread)
- INET/inet_error: select in packet_receive errno = 9
- INET/inet_error: connect errno = 111

I have found an explanation for the 111 one at
http://www.ipsiamoretto.com/~azzani/borland/interbase-faq/ (seems to
have no importance if you find a "/usr/lib/firebird/bin/ibguard:
guardian starting bin/ibserver" after it) and also a possible solution
for the 104 one (increasing "V4_LOCK_MEM_SIZE" from the default value of
"98304" to "196608").

About the error no. 32, I have found this:

http://ccm.redhat.com/bboard-archive/webdb/0006cP.html

So, since I am accessing the Firebird database from Php, it's supposed
that I should increase the timeout value somewhere in Php files,
shouldn't I?

I am also having a look at this doc:
http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_sem_sm

It seems pretty good, except for the fact that I speaks from a
theoretical point of view and the lack of examples. I'll keep on reading
anyway; several pretty interesting things on it...

Any hints?

--
Jaume Sabater
http://linuxsilo.net

"Ubi sapientas ibi libertas"