> I've tested it on 3 machines, all with the same error.

What Firebird version do you use? What version of JayBird do you use?
Can you try latest CVS version (that's the version I used)?

> With more testing i come to the conclusion that
> datasource.setMinConnections(5) creates the error.

No, it does not cause it, it only makes it visible earlier.

> But if i don't specify minConnections with value >0 i do not get any
> single connection.

Try to configure log4j with debug level and start your server with
-DFBLog4j=true, but I suspect that you will see that "host "e" is not
found"... I would understand when you get this error with RC2, where
no local protocol is available (but then I do not understand why does
it allow you to set "LOCAL" protocol :)), but with the version I sent
you this problem should dissapear. But anyway, please post the log
output on the debug level.

Roman