If you are connecting to a MS-SQL server from another win32 box, then you don'y really need to bother with the DBD::Sybase module.

This is the code that I have (using DBD::ODBC) which works just fine:

sub connectdb {
    my ($data_source, $database, $user_id, $passwd ) = 
        qw( server_hostname_or_IP database_instance username password 
+);
    my $conn_string = "driver={SQL Server};Server=$data_source;Databas
+e=$database;UID=$user_id;PWD=$passwd";
    my $dbh = DBI->connect( "DBI:ODBC:$conn_string" ) or die $DBI::err
+str;
    return $dbh;
}
[download]

Cheers,
Darren :)

PS. It's when you try connecting to a MS-SQL server from a Linux box that the fun really begins! But in that case, I found this tutorial to be an absolute godsend :)