Sorry about all this I'm totally new to Flash...
OK, since my post I've solved some of the problems:
all the MCs are named correctly - i'm certain (case and all.)
Here is the important bit of the code now, it sits on a button in the _root.Nav. level, and when its pressed makes 2 MCs on the _root level play, and is SUPPOSED to make an MC in the _root.Nav. level play called one. I am calling this like so:
_root.Nav.one.gotoAndPlay (2);
But it will not play.
Here is the code that matters:
on (release) {
nav = "1";
_root.HomeSeq.gotoAndStop(1);
_root.Tab2.gotoAndStop(1);
_root.Tab3.gotoAndStop(1);
_root.Tab4.gotoAndStop(1);
_root.ClearSeq.gotoAndPlay(2);
_root.Nav.one.gotoAndPlay(2);
_root.Nav.two.gotoAndStop(1);
_root.Nav.three.gotoAndStop(1);
_root.Nav.four.gotoAndStop(1);
if (nav == "1"

{
_root.Main1.gotoAndPlay(2);
_root.Main2.gotoAndStop(1);
_root.Main3.gotoAndStop(1);
_root.Main4.gotoAndStop(1);
}
What happens at the moment is that everything residing on the _root. level plays fine. BUT the _root.Nav.one, _root.Nav.two, _root.Nav.three etc. sub-levels will not play?
So, all the lines work except these:
_root.Nav.one.gotoAndPlay(2);
_root.Nav.two.gotoAndStop(1);
_root.Nav.three.gotoAndStop(1);
_root.Nav.four.gotoAndStop(1);
I can send you an fla if you give me your email?
Will the gotoAndPlay commands above only work if preceded by an 'if' statement perhaps like the ones that work? I'm totally stuck!
Thank you for your help