> Of course. Isn't it described in RN ?

No, I can not find it, only in Bug-fix section is mentioned bug CORE-1207, but this is IMO related only to embedded

> May be it is time to show us error message ?

SQLCODE=-904 "unavailable database"
(isql using connect "path_to_db" user sysdba password masterkey;)

When I use connect "localhost:path_to_db" (INET)... works ok
When I uncomment in firebird.conf IpcName=Global\FIREBIRD ... all works ok (also connect "path_to_db" XNET, also INET)

TIA
-Laco.