Yes... you're on the wrong page. Again, I recommend calling the order in. You can talk directly to a salesperson...you can even mention "ZazaSlider" and they know the parts.
You might want to order the rail without any pre-drilled holes...if so, just add an "S" to the end of the part number. (WS-16-60S)
1-888-803-1895
This is where you want to be:
http://www.igus.com/show_dw.asp
I did it all through eMail. No issues.
Yesterday I bought the nylon end caps and bolts.
Was a little difficult to find in HD but found em. Only cost me $13..
Had to buy another tapper to tap the holes.