Thanks again, all this has been very helpful and my wall is built, I am addicted to DF now, its awesome and those vid tuts along with the masses of input on the forums + wiki has given me a kick start. It a rare case to play a classic of a game so its great to finally find one again.
BTW I think this was my problem:
With UPSLOPES//RAMPS they already have places to stand, so it could be suspended, but for DOWNSLOPES//RAMPS, they are essentially open spots for that Z level. Which means if the wall on the solid ground is already built, your masons have no way to even reach the wall to build it. You either have to build a floor right next to it or deconstruct the wall next to it.
I notice in this tut further on the guy builds floors as well.
Alot of you have been telling me how bad elfs are so I did a crazy thing last night! basically a trader came and I wasnt thinking and sold them stuff with tree in them so they refused to trade at all, It would be good to be able to just display stuff that the trader is happy to buy and wont upset them. What I ended up doing was seiging some of the elf merchants stuff lol, so Im guessing I will be in trouble soon! I plan to do my fortress again soon anyway, just intrigued to see how things work out. My plan is to get a basic understanding of all the elements in game so soon I will aim to learn about aquifiers, redirecting streams , wells etc and once I know whats needed I can cut out my fortress in one foul swoop and be more oranised.
One final thing ! Merry Christmas! I was actually thinking, imagine if the head developer of the game put an easter egg in that on christmas day all your saves got deleted and a big message came up saying "Merry Christmas haha"