Inet Error 10061 in interbase.log

[HE]

I use com+ objects to access Interbase in my site web
Com+ object use FIB Components.

After a few hours ( 20 hours, one day) acces to interbase is impossible
(with com+ object or ibconsole).
With ibconsole, access to the server is refused by the server.

in the interbase log i have an 10061 error.

any idea of the reason(s) of this type of problem ?

The problem is the same with Firebird 0.9 or Interbase 6.01

The server web is iis5, Windows 2000 sp1 server.
Interbase server is on the same server.
ram 256 mo
Intel p4 800 mhz

Error 10061 is described by microsoft doc as

WSAECONNREFUSED
(10061)
Connection refused.
No connection could be made because the target machine actively refused it.
This usually results from trying to connect to a service that is inactive on
the foreign host - i.e. one with no server application running.

Thanks by advance for some help...