Hi There,
Actually, I think you could be wrong there. I got this syntax from http://search.cpan.org/~mewp/DBD-Sybase-1.04/Sybase.pm.
If you built DBD::Sybase with OpenClient 12.5.1 or later, then you can use the host and port values to define the server you want to connect to. This will by-pass the server name lookup in the interfaces file. This is useful in the case where the server hasn't been entered in the interfaces file.
$dbh = DBI->connect("dbi:Sybase:host=db1.domain.com;port-4100",$user, $passwd);
Plus, this script does work fine on my other linux machine. Although I know where you're coming from as I made the same mistake myself cause I used to connect to mysql databases. If I was to connect to mysql it would look like:
$dbh = DBI->connect("DBI:mysql:database=$database;host=$host;port=$port", "$username","$password")