I'm having a problem with connecting a video wall to my macbook. The video is going out of my macbook (minidisplayport) and into a minidisplayport to hdmi adaptor. from there it goes into a kramer splitter, which distributes the signal to a videowall, and two plasma screens. the videowall displays no image but the plasmas do.

When i connect my mac pro (dvi) into a dvi to hdmi adaptor,and then into the same splitter as the first example, everything works fine.

Can anyone explain why this is so?