one button 2 books and 1 track

HEy guys, i had a shitty problem the whole day..

I connect two laptops one macbook pro and one vista laptop,

i have a ip midi over ethernet cable running,
the bpm is syncro is not ok but it works i can send a signal on the mac or windows laptop to the other one.

everythin is ok

but how can i play the same track twice on laptop and macbook with one knob on one midikontroller

i mapped the playbutton from the vci 300 with the note G#3
i send it over the ipmidi output tu my macbook
it shows me that midi is comming in if i hit the knob on the vci300 on the windows laptop.
but the it doesnt start.
my mapping on the macbook is the same as the play button on the windows laptop,

but it doesnt work. why???

please help us
its cold in the cellar