Well DVI is not spec'd for anything more than 5 meters so a 15m cable without any sort of repeater of anything is a sketchy proposition.
I would suggest reviewing this page, if you have not already, which details in a very basic manner, DVI and all it's different aspects. http://www.datapro.net/techinfo/dvi_info.html
Things I would look for are what type of inputs and outputs are you dealing with on your various components? DVI-A? DVI-D? Dual Link? Single Link?
Hope this helps