Thanks for the tipp, i tried it and hell ... just as i assumed ... everything looks perfect.
So, here is the output of Dumper(%addrule_nat);

%addrule_nat = (
                 'protocol' => 'tcp',
                 'to-destination' => '10.0.1.2',
                 'destination-port' => '6990',
                 'jump' => 'DNAT'
               );
[download]

But still, IPTables::IPv4 reports the error msg:

"protocol: Must be passed as integer or string at..."

Hmm maby i will drop the Author of IPTables::IPv4 a mail.
But still, every tipp is welcome :)!

And by the way, of course i trust my best friends.

nermd