displayport cables

is there a certain standard for these things as i bought two of these and a display port coupler as i needed a 10m cable and neither of them work on there own or joined together.

the display port cable that came with my hp zr24w works fine so its definitely the cables that dont work.

http://cpc.farnell.com/pro-signal/ps...-5m/dp/AV18728

http://www.cablesandmore.co.uk/displ...ler-joiner.php

i also got two of these as well for the 5850

http://cpc.farnell.com/pro-signal/ps...10m/dp/AV19039

when i plug both of these in the disply port turns off, so i take it i screwed up and got the rong cables and should have got some of these.:confused:

http://cpc.farnell.com/_/cdl-dv06/le...-2m/dp/CS18701

there the same as im using now and all 3 monitors are working so i gess the 5850 dont like using dual link dvi cables with the display port.